What is Chemistry?

What is Chemistry?

The study of the properties of matter and the changes

that matter undergoes.

What is the modern definition of the atom?

What is the modern definition of the atom?

The smallest representative particle of an element that has all of the properties of that element.

What is an element?

What is an element?A substance that cannot be

separated into simpler substances by chemical means. All atoms of an element are alike in properties and reactivities.

What is a molecule?

What is a molecule?

A molecule is formed when two or more atoms bond covalently.

What are the four states of matter in order of increasing energy?

What are the four states of matter in order of increasing energy?

solid→ liquid→gas→plasma

What is the Law of Constant Composition?

What is the Law of Constant Composition?

The elemental composition of a pure compound is always the same.

What is the difference between a chemical and physical change?

In a physical change the substance alters its appearance, but not its chemical composition.

Water becomes ice, but is still H2O

In a chemical change, the substance is transformed into a different substance.

All changes of state are what type of changes?

All changes of state are what type of changes?

Physical

All combustion reactions are what type of reaction?

ChemicalCombustion reactions always have O2 as a reactant.

What are the three subatomic particles that chemists are concerned with?

Protons, neutrons and electrons

What is the electrical charge of a proton or electron?

1.602 x 10-19C is the amount of charge per electron or proton.

Protons positiveElectrons are negative

For simplicity, what do we consider to be the charge on an electron or proton?

-1 electron+1 proton

How do the number of protons and electrons compare in an atom of an element?

They are equal.

Which subatomic particles are found in the nucleus of an atom?

Protons and neutrons

What makes up most of the volume of an atom?

The electron cloud

Atoms have extremely small masses (the heaviest atom is on the order of 4 x 10-22 g) We use the amu to describe the mass of atoms and molecules. What is the amu?

The atomic mass unit. The mass of a proton and neutron are both considered to be 1 amu. An electron is about 2000 times smaller than a proton and is considered to be 0 amu.

On what element was the amu based?

On what element was the amu based?

Carbon -12

Atoms are extremely small. Most have diameters on the order of 10-10 m. What unit is commonly used to express the diameter of atoms?

Picometers and the Angstrom (Å)

1 Å = 10-10 m1pm = 10-12 m

The diameter of a carbon atom is 1.54 Å, express this diameter in picometers.

1.54Å x (10-10m) x (1012pm)

1Å 1m

=154 pm

What are the four basic forces?

What are the four basic forces?

GravitationalElectromagneticStrong nuclear forceWeak nuclear force

Which subatomic particle determines the identity of the element?

Which subatomic particle determines the identity of the element?

The number of protons determines the element

Each atom of an element has the same number of protons.

What are isotopes?

What are isotopes?Atoms of a given element that have different numbers of neutrons.

What is the atomic number?

The number of protons

What is the mass number?

What is the mass number?

The total number of protons and neutrons in the atom

How do we identify isotopes

Mass number Symbol Atomic number

For example

12C6

What is a nuclide

What is a nuclideAn atom of a specific isotope

How protons, neutrons and electrons are in an atom of 197Au.

All atoms of Au have 79 protons.

It is an atom so there are 79 electrons

There are 197 – 79 =118 neutrons

How many protons, electrons and neutrons are in an atom of 138Ba?

How many protons, electrons and neutrons are in an atom of 138Ba?

Protons and electrons 56138 -56 = 82 neutrons

Magnesium has three isotopes with mass numbers 24,25,and 26. a.)write the complete chemical symbol for each of these three isotopes b.)How many neutrons are in a nuclide of each isotope?

24Mg 25Mg 26Mg12 12 12

b.) 12, 13, and 14

Give the complete chemical symbol for the nuclide that contains 82 protons, 82 electrons and 126 neutrons.

208 Pb82

How is the atomic mass unit currently defined?

1/12 the mass of a carbon 12 nuclide

How is the average atomic mass of an element determined?

It is a weighted average. The masses of the various isotopes and their relative abundances are used.

Atomic weight is also known as the average atomic mass. Atomic mass is listed on the periodic table.

Naturally occurring chlorine is 75.78% 35Cl, which has a mass of 34.969, and 24.22% 37Cl which has an atomic mass of 36.966 amu. Calculate the average atomic mass of chlorine.

(.7578)(34969amu) + (.2422)(36.966)

26.50 amu + 8.953 amu

= 35.45 amu

Three isotopes of silicon occur in nature: 28Si (92.23%) with a mass of 27.97693 amu ;29Si (4.68%) with a mass of 28.97649 ; 30Si (3.09%) with a mass of 29.97377 amu. Calculate the atomic weight of silicon.

(.9223)(27.97693 amu) +

(.0468)(28.97649 amu) +

(.0309)(29.97377 amu)

=28.09 amu

What is the Periodic Table?

What is the Periodic Table?It is a very important tool that chemists use to organize and remember chemical facts.

What is the Periodic Table?The elements are arranged in order of increasing atomic number. The elements with similar properties are found in the same vertical columns.

What do we call the vertical columns on the periodic table?

What do we call the vertical columns on the periodic table?

A group or family

Why are the elements within a family similar in properties and chemical reactivity?

Why are the elements within a family similar in properties and chemical reactivity?

They have the same number of valence electrons

What are the common names associated with the following groups?

Group 1- Alkali metalsGroup 2 –Alkaline earth

metalsGroups 3-12 - Transition

metals

Group 13- Boron family

Group 14- Carbon family

Group 15- Nitrogen family

Group 16- Oxygen family

Group 17- Halogens

Group 18- Noble gases

Where are the metals on the periodic table?

The metals are found to the left of the metalloids.

Most elements are metals.

Nonmetals?

Nonmetals are found to the right of the metalloids.

Metalloids?

The metalloids separate the metals and nonmetals.

All elements except Al and Po that border the zig zag line are metalloids.

What are characteristics of metals?

What are characteristics of metals?

High lusterGood conductors of heat

and electricityMalleableDuctileTend to lose electrons

What are characteristics of nonmetals?

DullPoor conductorsBrittleTend to gain electrons or to

bond covalently with other nonmetals

What is the only family of elements in which the atoms are found in nature as isolated atoms?

The noble gases

What is a molecule?

What is a molecule?

Two or more atoms bonded covalently.

Most molecular substances contain only nonmetals

What is a diatomic molecule?

What is a diatomic molecule?

A molecule composed of two atoms of the same type.

What are the 7 diatomic molecules?

What are the 7 diatomic molecules?

F2 Cl2 Br2 I2 H2 O2 N2

The halogens HON!

What is a molecular formula?

What is a molecular formula?

A chemical formula that indicates the actual number and types of atoms in a molecule.

What is an empirical formula?

Chemical formulas that give only the smallest whole number ratio of types of atoms.

What is the empirical formula for

a.)C6H12O6

b.) N2O

c.) B2H6

What is the empirical formula for

a.)C6H12O6 - CH2O

b.) N2O - N2O

c.) B2H6 - BH3

What are structural formulas?

What are structural formulas?

Structural formulas show which atoms are bonded to each other in the molecule.

What are some examples of structural formulas?

Lewis structuresPerspective drawingBall and stickSpace filling models

What is an ion?

What is an ion?When electrons are gained or lost from an atom, the atom becomes an ion.

What is a cation?

What is a cation?When electrons are lost the atom becomes a positively charged ion or a cation.

What is an anion?

What is an anion?When electrons are gained the atom becomes a negatively charged ion or an anion.

Which elements form cations?

The metals tend to form cations because they tend to lose electrons.

Which elements form anions?

The nonmetals tend to form anions because they tend to gain electrons.

How can you predict the charge that an ion will have?

How can you predict the charge that an ion will have?Look at the number of

valence electrons the atom has. Then determine the number of electrons that would need to be lost or gained to have a full valence shell.

What is a polyatomic ion?

What is a polyatomic ion?

An ion composed of more than one atom bonded together covalently. The entire group has a charge.

What is a monatomic ion?

An ion that originated from a single atom. “ A single atom ion”

Define an ionic compound.

Define an ionic compound.

A compound consisting of ions.

Ionic compounds are typically combinations of metals and nonmetals

What type of formula do we use to describe ionic compounds?

What type of formula do we use to describe ionic compounds?

The empirical formulaIonic compounds tend to

have large numbers of ions bonded together in the crystal lattice. The empirical formula gives the ratio of ions

What is the criss cross method?

What is the criss cross method?

A method used to determine the formula for ionic compounds. The charge for one ion becomes the subscript for the other.

How can you predict if a compound is ionic or covalent?

If the substance has a metal and a nonmetal it is probably ionic

If the substance has two nonmetals it is probably covalent.

Which of the following would you expect to be ionic?

N2O Na2O CaCl2

SF4 CBr4 FeS

P4O6 PbF2

Which of the following would you expect to be ionic?

N2O Na2O CaCl2

Covalent ionic ionic

SF4 CBr4 FeSCovalent covalent ionic

P4O6 PbF2

Covalent ionic

What is the formula for the following compounds?

Aluminum oxide

Magnesium nitrate

Zinc sulfate

Iron III Carbonate

Sodium phosphate

Iron II chloride

What is the formula for the following compounds?

Aluminum oxide – Al2O3

Magnesium nitrate – Mg(NO3)2

Zinc sulfate- ZnSO4

Iron III Carbonate- Fe2(CO3)3

Sodium phosphate- Na3PO4

Iron II chloride – FeCl2

Naming Inorganic ionic compounds

Name the cation first.* The cation is always named before the anion.*cations named from a metal have the same name as the metal ( Al+3 is an aluminum ion)

Naming Inorganic ionic compounds

* Ions formed from a single atom are called monatomic ions.

* If the ion can have more than one charge, a roman numeral must be used to indicate charge.

Naming Inorganic ionic compounds

For example:

Iron II – Fe+2

Iron III – Fe+3

Naming Inorganic ionic compounds

If the ion is formed from several atoms covalently bonded to each other, it is a polyatomic ion.

Ammonium – NH4+

Sulfate – SO4-2

Naming Inorganic ionic compounds

Name the anion

Monatomic ions are named by replacing the ending with –ide.

Hydrogen becomes hydride

Oxygen becomes oxide

How do you identify polyatomic ions with oxygen?They end in –ate for the most common form, and –ite for the anion that has the same charge but one less oxgen.

With respect to polyatomic ions, what do the following prefixes indicate?

Per- indicates one more oxygen than the oxyanion with the –ate ending.

Hypo- one less oxygen than the -ite oxyanion

With respect to polyatomic ions, what do the following prefixes indicate?

ClO4- perchlorate

ClO3- chlorate

ClO2- chlorite

ClO- - hypochlorite

How are anions derived by adding a H+ named?

How are anions derived by adding a H+ named?

By adding as a prefix the word hydrogen for one hydrogen or dihydrogen for two hydrogen atoms.

How are anions derived by adding a H+ named?

For every hydrogen that is added the negative charge on the anion is decreased by one.

examples

CO3-2 Carbonate

HCO3- hydrogen carbonate

PO4-3 Phosphate

H2PO4- dihydrogen Phosphate

The formula for selenate is SeO4

2-. Write the formula for the selenite ion.

The formula for selenate is SeO4

2-. Write the formula for the selenite ion.-ate is changed to -ite so one

less oxygen is present.SeO3

2-

The formula for the bromate ion is BrO3

-. Write the formula for the hypobromite ion.

The formula for the bromate ion is BrO3

-. Write the formula for the hypobromite ion.

BrO-

Name the following compoundsa.) K2SO4

b.) Ba(OH)2

c.) FeCl3

Name the following compounds

a.) K2SO4 –Potassium sulfate

b.) Ba(OH)2 – Barium hydroxide

c.) FeCl3 – Iron III chloride

Name the following compoundsa.) NH4Br

b.) Cr2O3

c.) Co(NO3)2

Name the following compounds

a.) NH4Br- Ammonium bromide

b.) Cr2O3 – Chromium III oxide

c.) Co(NO3)2 – cobalt II nitrate

Write the chemical formula for the following compounds

Potassium sulfide

Calcium hydrogen carbonate

Nickel II perchlorate

Write the chemical formula for the following compounds

Potassium sulfide

K2SCalcium hydrogen carbonate

Ca(HCO3)2

Nickel II perchlorate

Ni(ClO4)2

What is the name for the following compounds?

MgSO4

AgS

Pb(NO3)2

What is the name for the following compounds?

MgSO4 – Magnesium sulfate

Ag2S – silver sulfide

Pb(NO3)2- lead II nitrate

Define an acid.

Define an acid.

A substance that has hydrogen ions as the cation and that yields H+ ions when dissolved in water.

How do you name an acid formed from a monatomic anion?Change the –ide ending of the anion to –ic and add the prefix hydro.

For example

HClH2SHBrH3N

For example

HCl hydrochloric acidH2S hydrosulfic acid ( May also

be hydrosulfuric acid)

HBr hydrobromic acidH3N hydronitric acid

Exception to the rule:

When the cyanide ion is used the acid is named as if it were a monatomic ion.

HCN is hydrocyanic acid

How do you name acids formed from polyatomic ions that have the –ate ending?

How do you name acids formed from polyatomic ions that have the –ate ending?Use the name of the

polyatomic anion but change the –ate ending to –ic and add the word acid.

Name H2CO3

Name H2CO3 You know it is an acid b/c

the cation is hydrogen.Take the carbonate name

change -ate to -ic and add the word acid.

Carbonic acid

Name H3PO4 You know it is an acid b/c

the cation is hydrogen.Take the phosphate name

change -ate to -ic and add the word acid.

Phosphoric acid

Name H2SO4 You know it is an acid b/c

the cation is hydrogen.Take the sulfate name

change -ate to -ic and add the word acid.

Sulfuric acid

For all acids, the number of hydrogen atoms is determined by the charge on the anion.

How do you name acids formed from polyatomic ions that have the –ite ending?

How do you name acids formed from polyatomic ions that have the –ite ending?Change the –ite ending to –ous

and add the word acid.

HNO2 – nitrous acid

H3PO3 phosphorous acid

H2SO3 sulfurous acid

Name the following acidsHCN

HNO3

H2SO4

H2SO3

Name the following acidsHCN hydrocyanic acid

HNO3 nitric acid

H2SO4 sulfuric acid

H2SO3 sulfurous acid

Naming molecular compounds

1.) The name of the element furthest to the left on the periodic table is usually written first.

Naming molecular compounds

2.) If both elements are in the same group, the lower one is named first.

Naming molecular compounds

3.) The name of the second element is given the suffix -ide.

Naming molecular compounds

4. Greek prefixes are used to indicate the number of atoms for each element. If the first element has only one atom, then a prefix is not used.

What are the prefixes that are used to indicate the number of atoms?

1- mono 6- hexa

2- di 7- hepta

3- tri 8- octa

4- tetra 9 – nona

5- penta 10- deca

Name the following

SO2

PCl5

N2O3

Name the following

SO2 – Sulfur dioxide

PCl5 – phosphorus pentachloride

N2O3 - dinitrogen trioxide

Give the formula for the following

A.) silicon tetrabromide

B.) disulfur dichloride

Give the formula for the following

A.) silicon tetrabromide – SiBr4

B.) disulfur dichloride – S2Cl2

What are organic compounds?

What are organic compounds?

Compounds that contain mainly hydrogen and carbon and often oxygen, nitrogen or other elements.

What are organic compounds?

Glucose – C6H12O6

Propane – C3H8

What are hydrocarbons?

What are hydrocarbons?

Compounds that contain only hydrogen and carbon

for example :C4H10

butane

What are alkanes?

What are alkanes?

A hydrocarbon in which carbon is bonded to four other atoms and all bonds are single bonds.

What are alkenes?

What are alkenes?

A hydrocarbon in which carbon is bonded to other carbon atoms and one or more of the bonds for carbon is a double bond

What are alkynes?

What are alkynes?

A hydrocarbon in which carbon is bonded to other carbon atoms and one or more of the bonds for carbon is a triple bond

What are the prefixes that are used to indicate the number of carbon atoms?

1- meth 6- hexa2- eth 7- hepta3- prop 8- octa4- but 9- nona5- pent 10 - deca

when naming hydrocarbons…

Alkanes end in –anei.e.,Methane, propane, heptane

Alkenes end in –enei.e., ethene, butene

Alkynes end in –ynei.e., propyne, pentyne

Hydrocarbons that have all single bonds are called saturated . If the hydrocarbon has one or more multiple bonds it is unsaturated.

what is an alcohol?

An alcohol is formed when a hydrogen on an alkane is replaced by an –OH group ( an hydroxyl group)

How are alcohols named.

Use the name of the alkane the alcohol was derived from and change the ending to -ol

what is an alcohol?Methane becomes methanol

Ethane become ethanol

Butane become butanol

what is an alcohol?

The properties of the alcohol are very different than the alkane they were formed from.