Pre-Comp Study guide(answers can be found at www.teacherweb.com/AZ/basisorovalley/hendon)

Multiple ChoiceFor questions 1-10, circle only one answer.

1. Any sample of matter has mass and takes up space.The main reason for this is because:a) All matter is heavy b) Matter can be a gasc) Matter is made up of tiny particles that have mass and take up space d) The Earth is made of matter

2. Water drops stay together on wax paper and they don’t break apart easily.This is mainly because:a) Water molecules are smallb) Water molecules are in motionc) Water molecules are attracted to each other d) Water molecules are wet

3. When you bring two drops of water near each other and allow them to touch, they combine immediately and become one drop.This is mainly because:a) Water molecules are made of atomsb) Water molecules are attracted to each other c) Water molecules are magneticd) Water is a liquid

4. If you put food coloring in room temperature water, the coloring spreads throughout the water.The water causes the color to spread mainly because:a) Water molecules are warmb) Water molecules are in motionc) Water is more dense than food coloring d) Food coloring molecules are small

5. Food coloring spreads out faster in hot water than in cold water.This is mainly because:a) The water molecules in hot water move more quickly b) The molecules in hot water are largerc) The food coloring molecules are small d) Hot water is less dense

6. When a thermometer is heated, the red liquid inside the thermometer moves up.This is mainly because:a) The red liquid is thin.b) The molecules of the liquid move faster and get a little further apart c) Hot liquid is lighterd) The glass of the thermometer gets hot

7. When a thermometer is cooled, the red liquid inside the thermometer moves down.This is mainly because:a) Cold liquids sinkb) The glass of the thermometer gets coldc) The molecules of the liquid move slower and get a little closer together d) The red liquid is thick

8. When you heat a sample of a solid, the particles that make up the solid:a) Get bigger b) Loose mass c) Move faster d) Slow down

9. When you heat a sample of a solid, the sample gets a little bigger.This is mainly because:a) The particles move faster and get a little further apart b) Heat helps the particles growc) Heating the sample makes it lighterd) Heating helps the particles slide past each other

10. When you heat a sample of gas, what happens to the particles that make up the gas?a) The particles move faster b) The particles break apart c) The particles get smallerd) The particles become more dense

For questions 11-13, circle all the correct answers.

11. To describe a liquid, you could say:a) The particles of a liquid are attracted to one another b) The particles of a liquid are in motionc) The particles of a liquid are able to move past one another d) A liquid has mass and takes up space

12. To describe a solid, you could say:a) The particles of a solid are attracted to each other b) The particles of a solid can move past one anotherc) The particles of a solid vibrate but do not move past one another d) A solid has mass and takes up space

13. To describe a gas, you could say:a) The particles are very attracted to each otherb) The particles are not very attracted to each other c) The particles are close together like a liquidd) The particles of a gas are further apart than the particles in a liquid or solid

True/False and Fill-in-the-blank

The three common states of matter are , , and .

True or False?The particles of a liquid are attracted to one another, but can’t move past each other.

is the study of matter.

True or False?An increase in temperature increases molecular motion and increases the distance between atoms and molecules in solids, liquids, and gases.

A in the speed of the molecules allows the attractions between molecules to bring them a little closer together.

True or False?Even when measuring the same temperature, the liquids in different thermometers can move to different heights depending on the liquid inside of them.

The molecules of the liquid inside the thermometer increase in speed when the thermometer is .

True or False?The atoms of a solid are very far apart and vibrate in fixed positions.

Cooling a solid the motion of the atoms.

True or False?Heating a gas completely stops all of its molecular motion.

True or False?Air has mass.

True or False?The molecules of a gas are not very attracted to each other.

Short Answer

If the particles of a liquid are always moving, why don’t they all come apart from each other and become a gas?

Water beads up on the surface of a freshly waxed car. If you use your finger to drag one drop very close to another and let them touch, the two drops quickly join together to become one bigger drop. What can you infer about water molecules based on this observation?

Even though water in a clear glass appears still, a drop of food coloring placed at the surface will slowly move throughout the water. Eventually, without stirring or shaking, the water will become evenly colored. What can you infer about water molecules based on these observations?

What do the circles and lines tell you about the arrangement, spacing, and speed of water molecules in room temperature water?

In a little more than a tablespoon of water, there are about 600 billion trillion water molecules. If you could count 1 million water molecules every second, it would take about 200 million centuries to count all the molecules in that tablespoon of water! What does this amazing fact tell you about the size of water molecules?

Compare the speed of molecules in hot water compared to molecules in cold water?

Draw circles and motion lines in each box to show differences in the movement and arrangement of water molecules in cold, room temperature, and hot water.

Thermometers have a very thin tube inside of them that stretches up from a round bulb, which holds most of the liquid.

a. Why does the red liquid move up the tube when a thermometer is heated?

b. Why does the red liquid move down the tube when a thermometer is cooled?

If two thermometers have different liquids in them, the liquids can move to different heights in the thermometers even if they are measuring the same temperature. Why does that happen?

You can make your own model of a thermometer like this one. Draw what happens to the molecules of red liquid in the skinny tube (like a juice pouch straw) when this thermometer is placed in hot and cold water.

Show the difference between the speed and spacing ofthe molecules in hot water and cold water. Draw circles in each straw below to represent water molecules. Use motion lines to represent the speed of the molecules.

Do you think that the particles of a solid or liquid are more attracted to each other? Why?

There is a metal ball and ring set that is specially made so that at room temperature the ball fits through the ring. However, when the ball is heated, it gets stuck and cannot fit through anymore.When heated, the ball actually gets a little bigger! Explain how the motion and attractions of the atoms in the metal ball cause it to get slightly larger when heated.

Describe what happens on the molecular level when a solid is heated.

In the demonstration with the metal ball and ring, why didn’t the ball fit through the ring after the ballwas heated with a Bunsen burner?

If the metal ring was cooled a lot, and the metal ball was at room temperature, would the ball still fit through the ring?

Sometimes on especially hot days, a wooden door, that opens and closes just fine during cooler months, will be hard to open and close. Why is the door hard to open and close on hot days? Hint: Think about the difference in the spacing of molecules in solids that are heated and cooled.

Is gas matter? How do you know?

The bottle in each picture is “empty” and has a thin film of bubble solution stretched over the top. When placed in a cup with hot water, a rounded bubble forms at the top. When placed in cold water, the bubble shrinks and turns inside out in the bottle. Answer the questions below by describing what each illustration is trying to show.

Why does a bubble form on the top of the bottle placed in hot water?

Why does the bubble shrink when the bottle is placed in cold water?

+ -

1) Cl2 2) H2 3) HCl 4) NaCl

1. _____ Which diagram best represents a polar molecule?a. 1b. 2c. 3d. 4

2. _____ Atoms of which of the following elements have the strongest attractions for electrons?a. Alb. Clc. Sid. Na

3. _____ Which element is most likely to gain electrons in a chemical reaction?a. Krb. Brc. Cad. Ba

4. _____ The P—Cl bond in a molecule of PCl3 is a. Nonpolarb. Polarc. Metallicd. Electrovalent

5. _____ The electrons in a bond between two iodine atoms (I2) are shareda. Equally, and the resulting bond is polar.b. Equally, and the resulting bond is nonpolar.c. Unequally, and the resulting bond is polar.d. Unequally, and the resulting bond is nonpolar.

6. _____ Which species does not have a noble gas electron configuration?a. Na+ b. Mg+2 c. Ard. S

7. _____ As a calcium atom undergoes oxidation to Ca+2 the number of neutrons in its nucleusa. Increaseb. Decreasec. Remain the same

8. A neutral atom changes to an ion with a charge of +3 bya. gaining 3 protonsb. losing 3 protonsc. gaining 3 electrond. losing 3 electrons

9. _____ What is the total number of electrons in the valence shell of an atom of aluminum in the ground state?

10. Write the electron configuration for a sodium ion. ________________________a. Identify the valence shell. _________

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

1) How many electrons are shared in a single covalent bond? 1. ________

A) 2 B) 3 C) 8 D) 1 E) 4

2) How many electrons are shared in a double covalent bond? 2. ________

A) 3 B) 6 C) 8 D) 2 E) 4

3) How many unshared pairs of electrons does the nitrogen atom in ammonia possess? 3. ________

A) 1 B) 2 C) 4 D) 5 E) 3

4) How do atoms achieve noble-gas electron configurations in single covalent bonds? 4. ________

A) Two atoms share two electrons. B) Two atoms share two pairs of electrons. C) Two atoms share one electron. D) One atom completely loses two electrons to the other atom in the bond.

5) Why do atoms share electrons in covalent bonds? 5. ________

A) to attain a noble-gas electron configuration B) to become ions and attract each other C) to become more polar D) to increase their atomic numbers

6) Which of the following is the name given to the pairs of valence electrons that do not participate in bonding in diatomic oxygen molecules? 6. ________

A) outer pair B) unvalenced pair C) bound pair D) unshared pair E) inner pair

7) Which elements can form diatomic molecules joined by a single covalent bond? 7. ________

A) hydrogen only B) halogens and members of the oxygen group only C) halogens only D) hydrogen, halogens, and members of the oxygen group E) hydrogen and the halogens only

8) A molecule with a single covalent bond is _____. 8. ________

A) CO2 B) CO C) Cl2 D) N2

9) A diatomic molecule with a triple covalent bond is _____. 9. ________

A) O2 B) F2 C) N2 D) H2

10) Which noble gas has the same electron configuration as the oxygen in a water molecule? 10. _______A) neon B) xenon C) argon D) helium

11) Which of the following diatomic molecules is joined by a double covalent bond? 11. _______

A) Cl2 B) O2 C) N2 D) H2

12) Which of the following pairs of elements can be joined by a covalent bond? 12. _______

A) N and C B) Na and C C) Mg and C D) Li and Cl

13) According to VSEPR theory, molecules adjust their shapes to keep which of the following as far apart as possible? 13. _______

A) pairs of valence electrons B) the electrons closest to the nuclei C) inner shell electrons D) mobile electrons

14) What causes water molecules to have a bent shape, according to VSEPR theory? 14. _______

A) ionic attraction and repulsion B) the unusual location of the free electrons C) interaction between the fixed orbitals of the unshared pairs of oxygen D) repulsive forces between specific electrons

15) The shape of the carbon tetrachloride molecule is called _____. 15. _______

A) planar B) tetrahedral C) four-cornered D) square

16) Which of the following covalent bonds is the most polar? 16. _______

A) C – C B) C – H C) C – Cl D) C – S E) C – Br

17) Which of the following atoms would acquire the most negative charge in a polar covalent bond with hydrogen? 17. _______

A) S B) O C) C D) F

18) Which of the following pairs of elements can be joined by a polar bond? 18. _______

A) C and C B) Na and C C) N and C

19) We would expect a bond formed between a silicon atom and an oxygen atom to be... 19. _______

A) a coordinate covalent bond B) a nonpolar covalent bond C) an ionic bond D) a polar covalent bond

20) Which of the following compounds is the most polar? 20. _______

A) CO B) CBr4 C) I2 D) NH3

21) What causes dipole interactions? 21. _______

A) attraction between polar molecules B) attraction between ions C) bonding of a covalently-bonded hydrogen to an unshared electron pair D) motion of electrons E) sharing of electron pairs

22) Which of the following causes the boiling point of HF to be much higher than that of HCl or HBr? 22. _______

A) coordinate covalent bonds B) hydrogen bonds C) covalent bonds D) van der Waals forces

23) Which type of solid has the highest melting point? 23. _______

A) nonmetallic solid B) network solid C) ionic solid D) metal

24) Which of the forces of molecular attraction is the weakest? 24. _______

A) hydrogen bond B) dipole interaction C) dispersion D) polar bond

25) Which of the forces of molecular attraction is the strongest? 25. _______

A) hydrogen bonds B) dipole interaction C) dispersion forces D) polar bond

Give the best short answer response or drawing to the following questions.

26) Given the molecule, CF4,

A) 2 pts. draw the Lewis dot structure. _________________

B) 2 pts. predict the shape of the molecule. _________________

C) 2 pts. What type of bond exists between the atoms? _________________ D) 4 pts. Is the overall molecule ionic, polar, or nonpolar? How do you know? _________________

____________________________________________________________________________________________________________________________________________________

27) Given the molecule, SH2,

A) 2 pts. draw the Lewis dot structure.

B) 4 pts. predict the shape of the molecule. _________________How do you know?

_____________________________________________________________________________________________________________________________________________

C) 2 pts. What type of bond exists between the atoms? _________________________

D) 2 pts. Is this molecule ionic, polar, or nonpolar? _________________________

28) Draw Lewis dot structures for the following compounds: (5 pts)

A) CO2 B) NH4+1 C) C2H2 D) HCN E) SO4 -2

Matching

Match each item with the correct statement below.

a. proton d. electron

b. nucleus e. neutron

1. a positively charged subatomic particle 2. a negatively charged subatomic particle 3. a subatomic particle with no charge 4. the central part of an atom, containing protons and neutrons

Match each item with the correct statement below.

a. mass number d. atomic mass

b. atomic mass unit c. atomic number

5. atoms with the same number of protons, but different numbers of neutrons in the nucleus of Atom

6. the total number of protons and neutrons in the nucleus of an atom 7. the number of protons in the nucleus of an element

Multiple Choice

Identify the choice that best completes the statement or answers the question.

_____ 8. Which of the following is true about subatomic particles?

a. Electrons are negatively charged and are the heaviest subatomic particle.

b. Protons are positively charged and the lightest subatomic particle.

c. Neutrons have no charge and are the lightest subatomic particle.

d. The mass of a neutron nearly equals the mass of a proton.

_____ 9. All atoms are _____

a. positively charged, with the number of protons exceeding the number of electrons

b. negatively charged, with the number of electrons exceeding the number of protons

c. neutral, with the number of protons equaling the number of electrons

d. neutral, with the number of protons equaling the number of neutrons

_____ 10. The particles that are found in the nucleus of an atom are .

a. neutrons and electrons

b. protons and neutrons

c. electrons only

d. protons and electrons

_____ 11. Rutherford’s gold foil experiment told us what about the atom?

a. Protons, electrons, and neutrons are evenly distributed throughout the volume of the atom.

b. The nucleus is made of protons, electrons, and neutrons.

c. Electrons are distributed around a small dense nucleus

d. The nucleus is made of electrons and protons.

_____ 12. The atomic number of an element is the total number of which particles in the nucleus?

a. neutrons and electrons c. electrons

b. protons d. protons and neutrons

_____ 13. An element has an atomic number of 76. The number of protons and electrons in a neutral atom of the element are _____.

a. 152 protons and 76 electrons c. 38 protons and 38 electrons

b. 76 protons and 0 electrons d. 76 protons and 76 electrons

_____ 14. The sum of the protons and neutrons in an atom equals the _____.

a. atomic number c. atomic mass

b. nucleus number d. mass number

_____ 15. All atoms of the same element have the same _____.

a. number of neutrons c. mass numbers

b. number of protons d. mass

_____ 16. The mass number of an element is equal to _____.

a. the total number of electrons in the nucleus

b. the total number of protons and neutrons in the nucleus

c. less than twice the atomic number

d. a constant number for the lighter elements

_____ 17. Using the periodic table, determine the number of neutrons in O.

a. 4 c. 16

b. 8 d. 24

_____ 18. Which of the following statements is NOT true?

a. Protons have a positive charge.

b. Electrons are negatively charged and have a mass of 1 amu.

c. The nucleus of an atom is positively charged.

d. Neutrons are located in the nucleus of an atom and have a mass of 1 amu.

_____ 19. The atomic mass of an element is the _____.

a. total number of subatomic particles in its nucleus

b. weighted average of the masses of the isotopes of the element

c. total mass of the isotopes of the element

d. average of the mass number and the atomic number for the element

_____ 20. How does the energy of an electron change when the electron moves closer to the nucleus?

a. It decreases. c. It stays the same.

b. It increases. d. It doubles.

_____ 21. When an electron moves from a lower to a higher energy level, the electron

a. does not change its energy c. absorbs energy

b. releases energy d. moves closer to the nucleus

_____ 22. What is the number of electrons in the outermost energy level of an oxygen atom?

a. 2 c. 6

b. 4 d. 8

_____ 23. Emission of light from an atom occurs when an electron _______

a. drops from a higher to a lower energy level

b. jumps from a lower to a higher energy level

c. moves within its atomic orbital

d. falls into the nucleus

Atomic Theory

Matching

Match each item with the correct statement below.

a. proton d. electron b. nucleus e. neutron c. atom

1. a positively charged subatomic particle 2. a negatively charged subatomic particle 3. a subatomic particle with no charge 4. the central part of an atom, containing protons and neutrons

Match each item with the correct statement below.a. mass number d. atomic mass b. atomic mass unit e. isotopec. atomic number

5. atoms with the same number of protons, but different numbers of neutrons in the nucleus of anatom

6. the total number of protons and neutrons in the nucleus of an atom 7. the number of protons in the nucleus of an element 8. the weighted average of the masses of the isotopes of an element

Multiple ChoiceIdentify the choice that best completes the statement or answers the question.

_____ 9. Which of the following is true about subatomic particles?c. Electrons are negatively charged and are the heaviest subatomic particle.d. Protons are positively charged and the lightest subatomic particle.c. Neutrons have no charge and are the lightest subatomic particle.d. The mass of a neutron nearly equals the mass of a proton.

_____ 10. All atoms are _____e. positively charged, with the number of protons exceeding the number of electronsf. negatively charged, with the number of electrons exceeding the number of protonsg. neutral, with the number of protons equaling the number of electronsh. neutral, with the number of protons equaling the number of neutrons

_____ 11. The particles that are found in the nucleus of an atom are .a. neutrons and electronsb. protons and neutronsc. electrons onlyd. protons and electrons

_____ 12. Rutherford’s gold foil experiment told us what about the atom?e. Protons, electrons, and neutrons are evenly distributed throughout the volume of the atom.f. The nucleus is made of protons, electrons, and neutrons.g. Electrons are distributed around the nucleus and occupy almost all the volume of the atomh. The nucleus is made of electrons and protons.

_____ 13. The atomic number of an element is the total number of which particles in the nucleus?a. neutrons c. electronsb. protons d. protons and electrons

_____ 14. An element has an atomic number of 76. The number of protons and electrons in a neutral atom of the element are _____.a. 152 protons and 76 electrons c. 38 protons and 38 electrons b. 76 protons and 0 electrons d. 76 protons and 76 electrons

_____ 15. The sum of the protons and neutrons in an atom equals the .a. atomic number c. atomic mass b. nucleus number d. mass number

_____ 16. All atoms of the same element have the same _____.a. number of neutrons c. mass numbers b. number of protons d. mass

_____ 17. Isotopes of the same element have different .a. numbers of neutrons c. numbers of electrons b. numbers of protons d. atomic numbers

_____ 18. The mass number of an element is equal to _____.e. the total number of electrons in the nucleusf. the total number of protons and neutrons in the nucleusg. less than twice the atomic numberh. a constant number for the lighter elements

_____ 19. Using the periodic table, determine the number of neutrons in O. a. 4 c. 16

b. 8 d. 24_____ 20. Which of the following statements is NOT true?

e. Protons have a positive charge.f. Electrons are negatively charged and have a mass of 1 amu.g. The nucleus of an atom is positively charged.h. Neutrons are located in the nucleus of an atom and have a mass of 1 amu.

_____ 21. The atomic mass of an element is the .e. total number of subatomic particles in its nucleusf. weighted average of the masses of the isotopes of the elementg. total mass of the isotopes of the elementh. average of the mass number and the atomic number for the

element_____ 22. In the Bohr model of the atom, an electron in an orbit has a fixed

a. position c. colorb. energy d. size

_____ 23. How does the energy of an electron change when the electron moves closer to the nucleus?a. It decreases. c. It stays the same. b. It increases. d. It doubles.

_____ 24. When an electron moves from a lower to a higher energy level, the electron a.does not change its energy c. absorbs energy

b. releases energy d. moves closer to the nucleus_____ 25. What is the number of electrons in the outermost energy level of an oxygen atom?

a. 2 c. 6b. 4 d. 8

_____ 26. Emission of light from an atom occurs when an electron _______e. drops from a higher to a lower energy levelf. jumps from a lower to a higher energy levelg. moves within its atomic orbitalh. falls into the nucleus

_____ 27. The atomic emission spectra of a sodium atom on Earth and of a sodium atom in the sun would be _____.

a. the sameb. different from each otherc. the same as those of several other elementsd. the same as each other only in the ultraviolet range

1.When water is changed from a liquid to a gas, what occurs?A) The atoms lose electrons.B) A new compound is formed.C) Molecules spread farther apart.D) Hydrogen is separated from oxygen.

2.Sodium chloride (NaCl) is formed in a chemical reaction between sodium (Na) and chlorine ( ). What is sodium chloride?A) an elementB) a mixtureC) a compoundD) an atom

3.When iron combines with oxygen in a moist environment, rust forms because of aA) chemical reaction.B) physical reaction.C) change in density.D) change in temperature.

4.Which set of elements below is the most similar in chemical behavior?A) H, Be, ScB) Fr, Ra, RfC) Ti, V, CrD) Be, Ca, Ra

5.The smallest part of an element that retains the properties of the element is theA) proton.B) nucleus.C) electron.D) atom.

6.Combining two nitrogen atoms at room temperature results in the formation of aA) mixture.B) compound.C) molecule.D) liquid.

7.When a molecule is separated into its component parts, it formsA) compounds.B) atoms.C) protons.D) ions.

8.Two elements in the same group on the Periodic Table of the Elements are most similar in theirA) atomic mass.B) number of protons.C) atomic size.D) chemical reactivity.

9.When potassium and bromine atoms form a chemical bond, which of these is produced?A) an elementB) a mixtureC) a compoundD) a new form of matter

10.Mixing baking soda and vinegar makes the temperature of the solution decrease and release carbon dioxide. Which conclusion about this investigation is not valid?A) Mixing the chemicals caused them to absorb heat.B) A chemical reaction took place.C) New elements were formed.D) The procedure caused a gas to be formed.

11.When heated, mercuric oxide decomposes to form liquid mercury and oxygen. A scientist heated 10 grams (g) of mercuric oxide and formed 9.3 grams of liquid mercury. How many grams of oxygen were formed?A) 0.7 gB) 9.3 gC) 10.0 gD) 19.3 g

12.In order to determine if two atoms are copper (Cu) atoms, what must be the same for each?A) the number of valence electronsB) the number of protonsC) the charge of the atomD) the size of the atom

13.A sodium (Na) atom contains 11 protons, 12 neutrons, and 11 electrons. In order to make the sodium ion what must occur to the sodium atom?

A) It must gain one electron.B) It must lose one electron.C) It must gain one proton.D) It must lose one proton.

14.The diagram shows the nuclei of some elements.

Which are nuclei of the same element?A) 1 and 2B) 1 and 3C) 2 and 4D) 3 and 4

15.Mr. Blackburn’s class studied some properties of four unknown substances. The table shows the properties the students observed.

Based on the table, which substance is most likely a metal?A) 1B) 2C) 3D) 4

16.Sodium (Na) and chlorine (Cl) combine to form sodium chloride (NaCl), which is commonly known asA) soap.B) vinegar.C) table salt.D) baking soda.

17.The atomic number of an element refers to the number ofA) electrons in the outer shell.B) neutrons in the outer shell.C) electrons in the nucleus.D) protons in the nucleus.

18.

Which parts of an atom are reactive during a chemical process?A) electronsB) protonsC) neutronsD) molecules

19.

Rust is a compound with the formula Which elements combine to form rust?A) iron and waterB) iron and oxygenC) iron and airD) iron and acid

20.

The number of neutrons in an atom is found by subtractingA) atomic number from mass number.B) mass number from atomic number.C) atomic number from electron number.D) isotope number from electron number.

21.

The formation of an ionic bond involves theA) transfer of electrons.B) sharing of neutrons.C) transfer of neutrons.D) sharing of protons.

22.If it is determined that the particles in one solid are arranged in a repeating pattern and the particles in another solid are arranged randomly, what must be true about the solids?A) They are different substances.B) They have the same weight.C) They have the same densities.D) They are different mixtures.

23.Which compound does not contain individual molecules?A) saltB) waterC) hydrogen gasD) carbon monoxide

24.

Which statement best describes the organization of the Periodic Table of the Elements?A) All gases are grouped together.B) Gases easily form compounds with other elements.C) Elements within a group have similar properties.D) Elements within a period have the same number of electrons.

25.Where in the Periodic Table of the Elements would shiny, malleable materials used in making jewelry be found?A) Group 1B) Group 4C) Group 11D) Group 17

26.

During photosynthesis, carbon dioxide and water combine according to the general equation:

Why is photosynthesis a chemical reaction?A) because new substances are formedB) because an input of energy is requiredC) because the reactants are compoundsD) because the products include an element

27.A bond is formed when an electron is transferred from a sodium atom to a chlorine atom. After the bond is formed, what happens to the sodium atom?A) The mass of the atom increases.B) The atom becomes an isotope.C) The atomic number decreases.D) The atom becomes a positive ion.

28.The noble gases, helium, neon, argon, krypton, xenon, and radon, rarely react with other elements because theyA) are low-density gases.B) are not abundant on Earth.C) have complete outermost energy levels.D) have two electrons in their outermost energy level.

29.

Read the equation.

What is the product of the reaction?A) metalB) mixtureC) solutionD) compound

30.When oxygen combines with hydrogen, which substance is formed?A) waterB) vinegarC) hydrochloric acidD) hydrogen peroxide

31.Atoms of the same element can have different atomic masses because they can have different numbers ofA) neutrons.B) protons.C) electrons.D) neutrinos.

32.The chemical formula for water is What does the formula show about each element in the compound?A) the number of valence electronsB) the charge of the compoundC) the mass of protons in each atomD) the number of atoms of each element

33.Magnesium bromide is one of the most abundant compounds found in sea water. Which formula correctly represents magnesium bromide?A) B) C) D)

34.

What is the name of the product formed from the reaction shown below?

A) ironB) iron oxideC) oxygen ferrideD) diferrous trioxide

35.An air-filled balloon shrank when moved from a warm room to a refrigerator. Which statement best explains why the balloon shrank?A) The number of molecules in the balloon decreased.B) The mass of the balloon decreased.C) Air pressure acting on the balloon increased.D) Density of the air in the balloon decreased.

36.Two forms of boron are naturally occurring, boron-10 and boron-11. What difference exists between a boron atom with a 10 atomic mass units (amu) and a boron atom with 11 atomic mass units (amu)?A) amount of neutronsB) number of electronsC) size of protons and neutronsD) size of electrons and electron cloud

37.

The diagram represents the chemical reaction that occurs when propane combusts.

In the reaction, for every molecule of propane, how many molecules of oxygen are used?A) 1B) 3C) 4D) 5

38.

In which pair of elements are both metalloids?A) Sn and SbB) Sb and TeC) Te and ID) I and Xe

39.Which set of elements has similar bonding properties?A) Cl, Br, and FB) K, Ca, and ScC) Kr, Cl, and OD) Be, C, and O

40.

The diagram for the structural formula of ethanol shows the elements and their arrangement.

What does the circled part of the diagram represent?A) an atomB) any ionC) one moleculeD) an electron

41.Which substance, when mixed with water, will produce the best conductor of electricity?A) table saltB) granulated sugarC) carbon dioxideD) motor oil

42.

The atoms that make up oxygen gasA) share two covalent bonds.B) have a definite shape.C) share a pair of neutrons.D) have two free electrons.

43.How many atoms are in one molecule of magnesium hydroxide, A) 6B) 5C) 4D) 3

44.Which substance is composed of only one type of atom?A) waterB) goldC) saltD) sugar

45.

How many atoms of oxygen are in a molecule of glucose, C6H12O6?A) 1B) 6C) 12D) 24

46.

Physical and chemical properties are listed below.

     1. malleable2. brittle3. highly combustible4. has free electrons

Which two of these properties apply to most elements that conduct heat?A) 1 and 3B) 1 and 4C) 2 and 3D) 2 and 4

47.The compound potassium sulfate, , is composed ofA) 2 atoms of potassium, 1 atom of sulfur, and 4 atoms of oxygen.B) 2 atoms of potassium, 4 atoms of sulfur, and 4 atoms of oxygen.C) two molecules of potassium and one molecule of sulfate.D) one molecule of potassium and two molecules of sulfate.

48.What number and types of atoms occur in a formula unit of A) 1 carbon atom, 1 neon atom, and 6 oxygen atomsB) 1 calcium atom, 2 neon atoms, and 3 oxygen atoms C) 1 carbon atom, 1 nitrogen atom, and 3 oxygen atomsD) 1 calcium atom, 2 nitrogen atoms, and 6 oxygen atoms

49.A solution was created by mixing an unknown powdery compound with distilled water. A conductivity test on the solution determined that the solution formed was a good conductor of electricity. Which statement is a valid conclusion based on this information?A) The solution is a base.B) The solution is an acid.C) The powdery substance is an ionic compound.D) The powdery substance is a covalent compound.

50.A student uses a golf ball to model the mass of a proton. Using the same scale, the student could most accurately model the mass of an electron by using aA) grapefruit.B) basketball.C) sand grain.D) plastic marble.