Chemistry Benchmark 1 Review - Thomas County School · PDF file · 2016-10-27Chemistry Benchmark 1 Review Completion Complete each statement. ... 16. Elements that have ... A paperclip

Chemistry Benchmark 1 Review

Completion

Complete each statement.

1. Chemistry is the study of _____________________ and the changes that it undergoes.

2. A(n) ______________________ is a set of controlled observations that test the hypothesis.

3. 100.00 meters 50.000 centimeters 1.0000 kilometer = ____________________ meters.

4. A process that involves one or more substances changing into new substances is known as a

____________________ change.

5. Cutting a sheet of paper is an example of a ____________________ change.

6. A ____________________ property enables a substance to combine with or change into one or more

substances.

7. Sugar is a ____________________ form of matter with a definite shape and volume.

8. A ____________________ is a subatomic particle that has mass nearly equal to that of a proton, but it carries

no electrical charge.

9. Atoms with the same number of protons but different number of neutrons are called ____________________.

10. An alpha particle is _____________________ charged with two protons and neutrons.

11. Democritus believed that matter is made up of tiny individual particles known as a(n)

____________________.

12. The number of protons in an atom is called the ____________________ of the element.

13. The ____________________ principle states that a maximum of two electrons may occupy a single atomic

orbital, but only if the electrons have opposite spins.

14. The arrangement of electrons in an atom is called the ____________________ of an atom.

15. The group 2A elements are known as ____________________ metals.

16. Elements that have physical and chemical properties of both metals and nonmetals are known as

____________________.

Short Answer

17. Explain the difference between mass and weight.

18. Explain how hypothesis and theory are different.

Use the figure below to answer the question.

19. Infer a qualitative measurement that can be made from the scene shown.

20. Infer a quantitative measurement that can be made from the scene shown.

21. What must be immediately done if chemicals come in contact with the eyes or skin while performing an

experiment in the laboratory?

22. Evaluate this dimensional analysis setup. A paperclip is 3.2 cm long. How many paperclips would fit in a

football field (100 yards) if 1 inch = 2.54 cm?

23. What two things does a conversion factor do?

24. The data for two different measurements are shown below. Which experiment was more accurate? Explain

your answer.

Sample Measured value Accepted value

Distance 54,700 m 57,900 m

Mass 61.3 g 65.7 g

A student conducts an experiment to determine the effect of adding salt on the boiling temperature of water.

The results are shown below.

Sample Amount of Salt Boiling Temperature

Sample 1 0 g 100.0° C

Sample 2 2 g 102.3° C

Sample 3 5 g 104.8° C

Sample 4 10 g 107.5° C

25. The student graphs this data using the axes shown. Is this graph correct? Explain your answer.

26. Define a base unit.

27. The distance between the earth and the sun is 90.0 million miles. Calculate this distance in meters up to three

significant digits.

28. Convert 600 mg to grams.

29. How many significant digits are there in 6.023 1023

molecules?

30. Identify both a physical change and a chemical change that could be done to a piece of paper.

31. Distinguish between element and compound.

32. Distinguish between homogeneous and heterogeneous mixtures. Give an example of each one.

33. Compare and contrast mass number and atomic mass.

34. What is the average atomic mass of this element?

Isotope Mass (amu) Percent Abundance

Phosphorus-29 29 5%

Phosphorus-31 31 71%

Phosphorus-32 32 24%

35. What is the average atomic mass of this element?

Isotope Mass (amu) Percent Abundance

Silver-105 105 48%

Silver-108 108 43%

Silver-109 109 9%

36. Write the chemical symbol for the isotope of cobalt with 37 neutrons.

37. Element X has an average atomic mass of 64.32 amu. If this element consists of only two isotopes, X-64 and

X-65, which isotope is present in the greater abundance? Explain how you can tell.

38. Define an atom.

39. What do you understand by the term atomic mass unit (amu)?

40. How are atomic number and mass number denoted in the chemical symbol of the isotope of an element?

Express the shortened notation for an isotope of element X with atomic number 92 and atomic mass 238.

41. Identify the element containing 34 protons.

42. What were the main flaws in Dalton’s atomic theory?

43. Summarize the relationship between wavelength, frequency, and energy of a wave.

44. A student records the following electron configuration for the element Arsenic (As). Evaluate this student’s

answer.

1s22s

22p

63s

23p

64s

24d

104p

3

45. Explain why it is only possible for two electrons to exist in the same orbital.

46. Use the model of the atom shown to identify the correct element. Write the electron configuration and orbital

diagram for this element.

47. Which rule for filling of orbitals by electrons in the element Silicon is being violated in the orbital diagram

shown? Justify your answer.

48. Which rule for the filling of orbitals in the element Phosphorus is being violated in the orbital diagram

shown? Justify your answer.

49. Which rule for the filling of orbitals by electrons in the element Magnesium is being violated? Justify your

answer.

50. Define a photon. What is the formula used to calculate the energy of a photon?

51. Why does a piece of iron appear red when heated sufficiently and blue at a higher temperature?

52. What is the ground state electron configuration of chlorine and the number of valence electrons in it?

53. How many valence electrons are present in cesium? Write the electron configuration of cesium if the atomic

number is 55.

54. Write the noble gas form of the electron configuration and the electron dot structure of sodium and oxygen.

55. Write the noble gas form of the electron configuration and the electron dot structure of selenium and

phosphorus.

56. A student makes the following statement: “It’s easy to tell which energy level an element is in - you just count

down which row it is in, and that’s the energy level.” Is this student correct? Explain how you came to your

conclusion.

57. Explain what is meant by the “octet rule.” Does it hold true for the modern periodic table?

58. Label the blank periodic table with the following terms.

A: metalloids

B: element with the highest electronegativity

C: alkali metals

D: lanthanide series

E: element with the greatest atomic radius

F: noble gases

G: halogens

59. Explain the significance of the stair-step line located near the right-hand side of the periodic table

60. Do the figures in this partial periodic table demonstrate the trend in atomic radius, ionic radius, or neither of

these? Relate your answer to the structure of atoms across the periodic table.

61. Place these five elements in order of electronegativity, with the highest electronegativity first.

62. Identify the representative elements from the list given below.

Na, Ca, Sc, Co, Ni, Si, N, Se, Cl, Ge

63. Why is argon placed before potassium in the modern periodic table?

64. Why do elements in the same group have similar properties?

65. Why is the size of a sodium ion (Na+) less than that of a sodium atom (Na)?

66. List the general electron configuration and location of the s, p, d, and f-block elements in the periodic table.

67. Use the periodic table to write the names of the third alkali metal and the first transition metal.

Problem

68. A vessel contains 30 mL of water. A sample of 5.0 g of copper metal is dropped into this vessel, raising the

level of water in it to 40 mL. What is the density of the copper sample?

69. When a 5.00-g metal piece, A, was immersed in 38.0 mL of water, the water level rose to 50.0 mL. Similarly,

when a 5.00-g metal piece, B, was immersed in 38.0 mL of water, the level of water rose to 60.0 mL.

Compare the density of the metal pieces, A and B.

70. Calculate the area of a rectangular piece of land with a length of 8.0 105 cm and a width of 4.0 10

3 cm.

Express your answer in meters.

71. Complete the following table:

Element Number of

protons

Number of

electrons

Number of

neutrons

Atomic

number

Mass number

Sodium 11 12

Phosphorus 15 31

Cobalt 27 32

Bromine 35 80

Silver 61 47

72. An element X has two naturally occurring isotopes: X-79 (abundance = 50.69%, mass = 78.918 amu) and

X-81 (abundance = 49.31%, mass = 80.917 amu). Calculate the weighted atomic mass of X. Also, identify the

unknown element which exists as a reddish-brown gas and is a liquid at room temperature.

73. An element X has three naturally occurring isotopes: X-24, X-25, and X-26. The atomic mass of X-25 is

24.986 amu and the relative abundance is 10.00 %. The atomic mass of X-26 is 25.982 amu and the relative

abundance is 11.01 %.Given that the weighted atomic mass of the element X is 24.305, calculate the mass

contribution due to the isotope X-24 and identify the element.

74. Calculate the number of protons, electrons, and neutrons in an atom of the element Pb with mass number 207

and atomic number 82.

75. Fluorine (F) contains 9 proton and 10 neutrons. Calculate its mass in amu for 81 atoms. (Given: mass of a

proton = 1.007276 amu, mass of a neutron = 1.008665 amu).

76. Lead contains 82 protons and 125 neutrons. Write the shortened notation of the element with its symbol,

atomic number, and mass number.

77. How many sublevels and orbitals are possible in the third energy level?

78. Write the ground state electron configuration of sulfur and draw its electron-dot structure.

79. Two elements A and B have atomic numbers 8 and 17 respectively. Identify their groups in the periodic table.

80. An element has similar chemical properties as oxygen and selenium. It has an atomic number greater than

krypton but less than iodine. Use the periodic table to identify the element.

81. Identify the element having the largest size and the element having the highest electronegativity from the list

of electron configurations given below:

a. [Ne] 3s23p

3

b. [Ne] 3s23p

4

c. [Ne] 3s23p

5

d. [Ne] 3s23p

34s

23d

3

82. Arrange the elements given below in the increasing order of their atomic size.

Element A 1s22s

22p

6

Element B 1s22s

2

Element C 1s22s

22p

63s

1

Element D 1s22s

22p

3

Chemistry Benchmark 1 Review

Answer Section

COMPLETION

1. ANS: matter

PTS: 1 DIF: 1 REF: Page 7 OBJ: 1.2.1 Define chemistry and matter.

NAT: B.2 STA: ABC 1.1 TOP: Define chemistry and matter.

KEY: Chemistry | Matter MSC: 1

2. ANS: experiment

PTS: 1 DIF: 1 REF: Page 11

OBJ: 1.3.2 Compare and contrast types of data. NAT: G.2

STA: ABC 1.1 TOP: Compare and contrast types of data.

KEY: Theory | Scientific law MSC: 1

3. ANS: 1100.5


OBJ: 2.1.2 Explain how adding a prefix changes a unit. NAT: UCP.1

STA: ABC 1.1 TOP: Explain how adding a prefix changes a unit.

KEY: Meter | Kilometer | Centimeter MSC: 2

4. ANS: chemical


OBJ: 3.2.2 Define chemical change and list several indications that a chemical change has taken place.

NAT: UCP.3 | B.3 STA: ABC 10.1

TOP: Define chemical change and list several indications that a chemical change has taken place.

KEY: Chemical change MSC: 1

5. ANS: physical


OBJ: 3.2.1 Define physical change and list several common physical changes.


TOP: Define physical change and list several common physical changes.

KEY: Physical change MSC: 2

6. ANS: chemical


OBJ: 3.1.2 Distinguish between physical and chemical properties.

NAT: B.2 STA: ABC 10.1 TOP: Distinguish between physical and chemical properties.

KEY: Chemical property MSC: 1

7. ANS: solid


OBJ: 3.1.3 Differentiate among the physical states of matter. NAT: B.2

STA: ABC 10.1 TOP: Differentiate among the physical states of matter.

KEY: Solids MSC: 2

8. ANS: neutron


OBJ: 4.2.2 Describe the structure of the nuclear atom, including the locations of the subatomic particles.

NAT: B.1 | G.3 STA: ABC 10.1 | ABC 10.2

TOP: Describe the structure of the nuclear atom, including the locations of the subatomic particles.

KEY: Neutron MSC: 1

9. ANS: isotopes


OBJ: 4.3.2 Define an isotope and explain why atomic masses are not whole numbers.

NAT: B.1 STA: ABC 10.1 | ABC 10.2

TOP: Define an isotope and explain why atomic masses are not whole numbers.

KEY: Isotopes MSC: 1

10. ANS: positively


OBJ: 4.4.2 Characterize alpha, beta, and gamma radiation in terms of mass and charge.

NAT: B.1 | B.6 STA: ABC 10.1 | ABC 10.2

TOP: Characterize alpha, beta, and gamma radiation in terms of mass and charge.

KEY: Alpha radiations MSC: 1

11. ANS:

atomos

atom


OBJ: 4.1.1 Compare and contrast the atomic models of Democritus and Dalton.

NAT: G.3 | UCP.2 | B.1 | B.2 STA: ABC 10.1

TOP: Compare and contrast the atomic models of Democritus and Dalton.

KEY: Atom MSC: 1

12. ANS: atomic number


OBJ: 4.3.1 Explain the role of atomic number in determining the identity of an atom.

NAT: B.1 STA: ABC 10.1

TOP: Explain the role of atomic number in determining the identity of an atom.

KEY: Atomic number MSC: 1

13. ANS: Pauli exclusion


OBJ: 5.3.1 Apply the Pauli exclusion principle, the aufbau principle, and Hund's rule to write electron

configurations using orbital diagrams and electron configuration notation.

NAT: B.6 STA: ABC 10.1 | ABC 10.2

TOP: Apply the Pauli exclusion principle, the aufbau principle, and Hund's rule to write electron


KEY: Pauli exclusion principle MSC: 1

14. ANS: electron configuration


OBJ: 5.3.1 Apply the Pauli exclusion principle, the aufbau principle, and Hund's rule to write electron



TOP: Apply the Pauli exclusion principle, the aufbau principle, and Hund's rule to write electron


KEY: Electron configuration MSC: 1

15. ANS: alkaline earth


OBJ: 6.1.1 Trace the development and identify key features of the periodic table.

NAT: G.3 | B.1 | UCP.1 STA: ABC 10.1

TOP: Trace the development and identify key features of the periodic table.

KEY: Alkaline earth metals MSC: 1

16. ANS: metalloids



NAT: G.3 | B.1 | UCP.1 STA: ABC 10.1


KEY: Metalloids MSC: 1

SHORT ANSWER

17. ANS:

Mass is a measurement of the amount of matter in a substance, while weight is a measure of gravity’s effect

on that mass.

PTS: 1 DIF: Bloom's Level 2 NAT: UCP.2 | E.2

STA: ES 9.1

18. ANS:

A hypothesis is a prediction of the outcome of one experiment. A theory is a description of how a process is

believed to occur and is based on the results of many different experiments.

PTS: 1 DIF: Bloom's Level 4 NAT: UCP.2 | A.2

STA: ABC 1.1

19. ANS:

Answers should be descriptions of object without using numbers (counting or measuring).

PTS: 1 DIF: Bloom's Level 3 NAT: UCP.3 | A.1 | A.2

STA: ABC 10.1

20. ANS:

Answers should include a numerical value obtained from measurement or counting.

PTS: 1 DIF: Bloom's Level 3 NAT: UCP.3 | A.1 | A.2

STA: ABC 10.1

21. ANS:

Flush the area immediately with large quantities of water and inform the teacher of the spill and the chemical.


OBJ: 1.4.2 Apply knowledge of laboratory safety. NAT: A.1 | A.2

STA: ABC 3.1 TOP: Apply knowledge of laboratory safety.

KEY: Laboratory safety MSC: 1

22. ANS:

The second conversion factor, 1 inch = 2.54 cm, is reversed. It needs to be arranged so that the unit in the

denominator of one fraction can cancel out the unit in the numerator of the next fraction, and so on.

PTS: 1 DIF: Bloom's Level 6 NAT: UCP.2

STA: ABC 1.1

23. ANS:

1. cancels one unit

2. introduces a new unit


STA: ABC 1.1

24. ANS:

The distance measurement has an error of 5.53%. The mass measurement has an error of 6.70%. Therefore,

distance was measured more accurately.

PTS: 1 DIF: Bloom's Level 6 NAT: UCP.2 | UCP.3

STA: ABC 1.1

25. ANS:

The independent variable should be placed on the X axis, and the dependent variable on the Y axis. This

graph is correct as shown.


STA: ABC 1.1

26. ANS:

A base unit is a defined unit in a system of measurement that is based on an object or event in the physical

world. It is independent of other units.


OBJ: 2.1.1 Define SI base units for time, length, mass, and temperature.

NAT: UCP.1 STA: ABC 1.1

TOP: Define SI base units for time, length, mass, and temperature.

KEY: Base unit MSC: 1

27. ANS:

1.44 1011

m


OBJ: 2.2.2 Use dimensional analysis to convert between units. NAT: UCP.1

STA: ABC 1.1 TOP: Use dimensional analysis to convert between units.

KEY: Miles | Meter MSC: 3

28. ANS:

1mg = 1/ 1000 g

600 mg = 0.6 g




KEY: Gram | Milligram MSC: 3

29. ANS:

There are four significant digits in 6.023 1023

molecules.


OBJ: 2.3.2 Use significant figures and rounding to reflect the certainty of data.

NAT: E.2 | G.2 STA: ABC 1.1

TOP: Use significant figures and rounding to reflect the certainty of data.

KEY: Significant figures | Molecules MSC: 2

30. ANS:

A physical change might be ripping it, crumpling it, or writing on it with pencils or pens. A chemical change

might be burning it or letting it rot.

PTS: 1 DIF: Bloom's Level 3 NAT: UCP.3 | B.2 | B.3

STA: ABC 10.1

31. ANS:

An element is the smallest piece of matter that retains its physical and chemical properties, and is made up of

only one type of atom. A compound is made of more than one different element chemically joined together. A

compound can be broken into smaller pieces by chemical means.


STA: ABC 10.1

32. ANS:

A homogeneous mixture is a combination of substances in varying proportions where the individual

substances cannot be distinguished. Every part of the mixture has the same composition as any other part,

such as in a beverage made from powdered mix. In a heterogeneous mixture, the different substances can be

distinguished. Parts of the mixture have different compositions, as in a chocolate-chip cookie.


STA: ABC 10.1

33. ANS:

Mass number is the total number of neutrons and protons in an individual atom. It is an integer number.

Atomic number, or average atomic number, is the weighted average mass of all of the different isotopes found

in a sample of an element. Because it is a weighted average, atomic mass is usually a decimal number.

PTS: 1 DIF: Bloom's Level 2 NAT: UCP.2 | B.1

STA: ABC 10.1 | ABC 10.2

34. ANS:

(29*.05)+(31*.71)+(32*.24) = 31.14 amu


STA: ABC 10.1 | ABC 10.2

35. ANS:

(105*.48)+(108*.43)+(109*.09) = 106.65 amu


STA: ABC 10.1 | ABC 10.2

36. ANS:

PTS: 1 DIF: Bloom's Level 3 NAT: B.1

STA: ABC 10.1 | ABC 10.2

37. ANS:

The more abundant isotope would be X-64. With only two isotopes, one can be certain that the weighted

average atomic mass will be closer to the isotope in greater abundance. Since the average mass is 64.32,

which rounds to 64, isotope X-64 must be more abundant than X-65.


STA: ABC 10.1 | ABC 10.2

38. ANS:

An atom is the smallest particle of an element that retains the properties of the element.

PTS: 1 DIF: 1 REF: Page 90 OBJ: 4.1.2 Define an atom.

NAT: B.1 STA: ABC 10.1 TOP: Define an atom.

KEY: Atom MSC: 1

39. ANS:

The atomic mass unit measures the mass of an atom relative to the mass of carbon-12 atom, which is taken as

a standard. One atomic mass unit is defined as 1/12 the mass of a carbon-12 atom.


OBJ: 4.3.3 Calculate the number of electrons, protons, and neutrons in an atom given its mass number and

atomic number. NAT: B.1 STA: ABC 10.1 | ABC 10.2

TOP: Calculate the number of electrons, protons, and neutrons in an atom given its mass number and atomic

number. KEY: Atomic mass unit MSC: 2

40. ANS:

The atomic number is written as the subscript in the chemical symbol of an element and the mass number is

written as the superscript in the chemical symbol of an element. The notation for an isotope of element X is

denoted as .

PTS: 1 DIF: 2 REF: Page 98 | Page 100


NAT: B.1 STA: ABC 10.1 | ABC 10.2


KEY: Atomic number | Mass number | Isotopes MSC: 3

41. ANS:

The element containing 34 protons is Selenium (Se).



NAT: B.1 STA: ABC 10.1 | ABC 10.2



42. ANS:

There were two main flaws in Dalton’s atomic theory.

a. Atoms are not indivisible. They are divisible into several subatomic particles.

b. All atoms of a given element may not have identical properties as their masses may vary slightly.


OBJ: 4.1.1 Compare and contrast the atomic models of Democritus and Dalton.

NAT: G.3 | UCP.2 | B.1 | B.2 STA: ABC 10.1 | ABC 10.2

TOP: Compare and contrast the atomic models of Democritus and Dalton.

KEY: Dalton's atomic theory MSC: 2

43. ANS:

As the amount of energy carried by a wave increases, the individual waves get closer together, increasing

their frequency but decreasing their wavelength.


STA: ABC 10.2 | ABC 10.3

44. ANS:

The “d10

” should be preceded by a 3; although the first set of d-block elements are in the fourth period, these

electrons are actually contained in the third energy level due to the overlapping of energy levels and orbitals.


STA: ABC 10.2 | ABC 10.3

45. ANS:

Electrons have a spin. In any given orbital, only two electrons can exist because one will spin in an “upward”

direction while the other one spins in a “downward” direction. A pair of electrons can only exist in an orbital

if they are spinning in opposite directions.


STA: ABC 10.2 | ABC 10.3

46. ANS:

The element is Silicon. The electron configuration is 1s2s2

22p

63s

23p

6. The orbital diagram is shown below.


STA: ABC 10.2 | ABC 10.3

47. ANS:

This violates the Aufbau principle, which states that electrons must fill in the orbital with the lowest amount

of energy before filling any orbitals with a greater amount of energy. In the diagram shown, electrons are

placed in the 3p orbitals before the 3s is filled.


STA: ABC 10.2 | ABC 10.3

48. ANS:

This is violating Hund’s rule. According to Hund’s rule, single electrons must occupy the orbitals within the

same energy level and type of orbital before two electrons are allowed to occupy the same orbital. Here, two

electrons occupy the first 3p orbital before the other two orbitals have one electron.


STA: ABC 10.2 | ABC 10.3

49. ANS:

The Pauli exclusion principle is being violated. The Pauli exclusion principle requires that if two electrons

occupy the same orbital, they must have opposite spin directions. This is generally shown by having arrows

pointing either up or down in the orbital diagrams. Here, the two electrons in the 3s orbital are spinning the

same direction, as indicated by the arrows pointing the same direction.


STA: ABC 10.2 | ABC 10.3

50. ANS:

A photon is a particle of electromagnetic radiation that has no mass and carries a quantum of energy. The

energy of a photon can be calculated using the formula Equantum h , where E is energy of the photon, h is

Planck’s constant, and is frequency of the photon.


OBJ: 5.1.1 Compare the wave and particle models of light. NAT: B.1

STA: ABC 10.2 | ABC 10.3 TOP: Compare the wave and particle models of light.

KEY: Photon | Energy levels MSC: 1

51. ANS:

A piece of iron appears red when heated sufficiently and blue at a higher temperature, because the kinetic

energy of iron increases when it is heated. With an increase in the amount of energy, different colors of light

are emitted. These colors correspond to different frequencies and wavelengths.


OBJ: 5.1.2 Define a quantum of energy and explain how it is related to an energy change of matter.


TOP: Define a quantum of energy and explain how it is related to an energy change of matter.

KEY: Quantum MSC: 2

52. ANS:

The ground state electron configuration of chlorine is 1s22s

22p

63s

23p

5. It has 7 valence electrons.


OBJ: 5.3.2 Define valence electrons and draw electron-dot structures representing an atom's valence

electrons. NAT: B.1 | B.6 STA: ABC 10.2 | ABC 10.3

TOP: Define valence electrons and draw electron-dot structures representing an atom's valence electrons.

KEY: Valence electrons | Electron configuration MSC: 2

53. ANS:

There is only one valence electron in cesium. The electron configuration of cesium with atomic number 55 is

[Xe]6s1.





KEY: Valence electrons | Electron configuration MSC: 1

54. ANS:

a. The noble gas form of the electron configuration of sodium is [Ne]3s1. Its electron dot structure is

b. The noble gas form of electron configuration of oxygen is [He]2s22p

4. Its electron dot structure is





KEY: Electron configuration | Electron-dot structure MSC: 2

55. ANS:

a. The noble gas form of the electron configuration of selenium is [Ar]4s24p

4. Its electron-dot structure is

b. The noble gas form of the electron configuration of phosphorus is [Ne]3s23p

5. Its electron-dot structure

is .





KEY: Electron configuration | Electron-dot structure MSC: 2

56. ANS:

No, the student is not correct. We know from writing electron configurations (Chapter 5) that elements in

each row of the d-block are actually contained in the energy level of the previous row; therefore one cannot

merely count down the rows. Periods and energy levels are not the same thing. One should also be careful

to not claim that the top row of the d-block is energy level 1 because it is the first row of that section.

PTS: 1 DIF: Bloom's Level 6 NAT: B.1 | B.6

STA: ABC 10.1

57. ANS:

The octet rule states that most elements would like to have eight electrons in their outer energy level to

become stable like the closest noble gas.


STA: ABC 10.1

58. ANS:


STA: ABC 10.1

59. ANS:

The stairstep line separates the metals from the nonmetals on the periodic table. Elements that are adjacent

to this line are considered metalloids and have some properties of metals and some properties of nonmetals.


STA: ABC 10.1

60. ANS:

These show the atomic radius change. As electrons are added to the outer energy levels of an atom (as one

moves across the periodic table), the size of the atom decreases. This is because the additional positive

charge in the nucleus attracts the electrons more strongly and no additional shielding effect occurs across the

period.

PTS: 1 DIF: Bloom's Level 4 NAT: UCP.2 | B.1 | B.2

STA: ABC 10.1

61. ANS:

B, D, C, E, A


STA: ABC 10.1

62. ANS:

Na, Ca, N, Si, Se, Cl, Ge



NAT: G.3 | B.1 | UCP.1 STA: ABC 10.1


KEY: Metals MSC: 2

63. ANS:

In the modern periodic table, the elements are placed in the order of their increasing atomic numbers. The

atomic number of argon is 18 while the atomic number of potassium is 19. Therefore, argon is placed before

potassium in the modern periodic table.



NAT: G.3 | B.1 | UCP.1 STA: ABC 10.1



64. ANS:

Elements in the same group have the same electron configuration and number of valence electrons. Valence

electrons determine the properties of elements. Therefore, properties of elements in the same group are

similar.


OBJ: 6.2.1 Explain why elements in the same group have similar properties.

NAT: UCP.1 | B.1 | B.2 STA: ABC 10.1

TOP: Explain why elements in the same group have similar properties.

KEY: Groups | Electron configuration MSC: 2

65. ANS:

The loss of an electron from a sodium atom results in a smaller radius. The electrostatic repulsion between the

remaining number of electrons decreases thus allowing them to be pulled closer to the nucleus. Therefore, the

size of a sodium ion (Na+) is less than that of a sodium atom (Na).


OBJ: 6.3.2 Relate period and group trends in atomic radii to electron configuration.

NAT: UCP.1 | B.1 | B.2 STA: ABC 10.1

TOP: Relate period and group trends in atomic radii to electron configuration.

KEY: Atomic size | Ionic radius MSC: 2

66. ANS:

The general electron configuration and locations of the block elements are:

a. ns0-2

for s-block elements in groups 1 and 2.

b. ns0-2

and np0-6

for p-block elements in groups 13, 14, 15, 16, 17, and 18.

c. (n–1)d0-10

and ns0-2

for d-block elements in groups 3, 4, 5, 6, 7, 8, 9, 10, 11, and 12.

d. (n–2)f0-14

, (n–1)d0-10

, np0-6

, and ns0-2

for f-block elements in lanthanide and actinide groups.


OBJ: 6.2.2 Identify the four blocks of the periodic table based on electron configuration.


TOP: Identify the four blocks of the periodic table based on electron configuration.

KEY: Electron configuration MSC: 1

67. ANS:

Potassium is the third alkali metal and scandium is the first transition metal in the periodic table.



NAT: G.3 | B.1 | UCP.1 STA: ABC 10.1


KEY: Alkali metals | Transition metals MSC: 1

PROBLEM

68. ANS:

0.5 g/mL


OBJ: 2.1.3 Compare the derived units of volume and density. STA: ABC 1.1

TOP: Compare the derived units of volume and density. KEY: Mass | Density | Volume

MSC: 3

NOT: Density = mass / volume. The volume of the copper sample is = 40 mL - 30 mL = 10 mL.

69. ANS:

Metal A has a greater density than metal B.

The density of metal A = 0.417 g/mL.

The density of metal B = 0.227 g/mL.


OBJ: 2.1.3 Compare the derived units of volume and density. STA: ABC 1.1

TOP: Compare the derived units of volume and density. KEY: Mass | Density | Volume

MSC: 3 NOT: Density = mass / volume

70. ANS:

3.2 105 m

2




KEY: Meter | Centimeter | Area MSC: 3

NOT: Area = length * width. 1m = 100 cm.

71. ANS:

Element Number of

protons

Number of

electrons

Number of

neutrons

Atomic

number

Mass number

Sodium 11 11 23

Phosphorus 15 16 15

Cobalt 27 27 59

Bromine 35 45 35

Silver 47 47 108

PTS: 1 DIF: 3 REF: Page 98 | Page 99 | Page 100




number. KEY: Composition of elements MSC: 3

NOT: Atomic number = number of protons = number of electrons. Mass number = number of protons +

number of neutrons.

72. ANS:

79.904 amu

Bromine





number. KEY: Atomic mass of isotopes MSC: 3

NOT: Weighted atomic mass of element X = mass contribution of X-79 + mass contribution of X-81. Mass

contribution of each isotope = (mass in amu of the isotope) * (percent abundance).

73. ANS:

23.985 amu

Magnesium





number. KEY: Atomic mass of isotopes MSC: 3

NOT: Weighted atomic mass of element X = mass contribution of X-24 + mass contribution of X-25 + mass

contribution of X-26. Mass contribution = (mass of the isotope in amu) * (percent abundance).

74. ANS:

Number of protons = atomic number = 82.

Number of electrons = number of protons = 82.

Number of neutrons = mass number – atomic number = 125.



NAT: B.1 STA: ABC 10.1 | ABC 10.2



NOT: Atomic number = number of protons = number of electrons.

75. ANS:

1551.32 amu





number. KEY: Mass of individual atoms MSC: 3

NOT: The mass of an atom depends on the number of protons and neutrons. It is expressed in atomic mass

units (amu).

76. ANS:



NAT: B.1 STA: ABC 10.1 | ABC 10.2


KEY: Chemical symbol and notation MSC: 3

NOT: Isotopes are written with a shortened type notation. The notation includes the chemical symbol, atomic

number and mass number. The atomic mass and the atomic number are written to the left of the chemical

symbol. The atomic mass is denoted as a superscript and the atomic number is denoted as a subscript.

77. ANS:

There are three sublevels and nine orbitals possible in the third energy level.


OBJ: 5.2.3 Identify the relationships among a hydrogen atom's energy levels, sublevels, and atomic orbitals.

NAT: B.6 STA: ABC 10.1 | ABC 10.2

TOP: Identify the relationships among a hydrogen atom's energy levels, sublevels, and atomic orbitals.

KEY: Energy levels | Sublevels | Atomic orbitals MSC: 2

NOT: The number of sublevels is equal to the types of orbitals. The number of orbitals is equal to all the

integers ranging from positive to negative values.

78. ANS:

The ground state electron configuration of sulfur is [Ne]3s23p

4. Its electron dot structure is





KEY: Electron-dot structure | Valence electrons MSC: 3

79. ANS:

Element A belongs to group 6A and element B belongs to group 7A in the periodic table.


OBJ: 6.2.1 Explain why elements in the same group have similar properties.

NAT: UCP.1 | B.1 | B.2 STA: ABC 10.1

TOP: Explain why elements in the same group have similar properties.

KEY: Groups MSC: 1 NOT: Groups indicate the number of valence electrons.

80. ANS:

Tellurium



NAT: G.3 | B.1 | UCP.1 STA: ABC 10.1


KEY: Periodic table MSC: 2

NOT: Elements are arranged in the increasing order of their atomic numbers. Elements in groups have

similar properties.

81. ANS:

The element having the largest size has an electron configuration of [Ne] 3s23p

34s

23d

3. The element having

the highest electronegativity has an electron configuration of [Ne] 3s23p

5.



NAT: UCP.1 | B.1 | B.2 STA: ABC 10.1


KEY: Electron configuration | Atomic size | Electronegativity MSC: 2

NOT: The size of the atom depends on the number of shells in an atom. Electronegativity increases across a

period.

82. ANS:

The arrangement of elements in the increasing order of their atomic size is B < A < D < C. Element B is the

smallest and Element C is the largest.



NAT: UCP.1 | B.1 | B.2 STA: ABC 10.1


KEY: Atomic size | Electron configuration MSC: 2

NOT: The size of an atom depends upon the number of shells in an atom. In the same period, the atomic size

decreases from left to right.

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