Composed of a Cation (+ charge) and an Anion (- charge).

Ionic compounds are electrically neutral.

Ionic compounds are composed of: A metal and a non-metal NaCl A metal and a polyatomic anion NaNO3

A polyatomic cation and a non-metal NH4Cl A polyatomic cation and a polyatomic anion

NH4NO3

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Metals form cations with + charges.

Group 1 metals form cations with a 1+ charge.

Cations are named with the metal’s name plus ion.

Li1+ Na1+ K1+ Rb1+ Cs1+ Fr1+.

Lithium ion, Sodium ion, Potassium ion, Rubidium ion, Cesium ion, Francium ion.

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Group 2 metals form cations with a 2+ charge.

Be2+ Mg2+ Ca2+ Sr2+ Ba2+ Ra2+

Beryllium ion, Magnesium ion, Calcium ion, Strontium ion, Barium ion, Radium ion.

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Other metals with only one oxidation state (charge):

Al3+ Aluminum ion

Zn2+ Zinc ion

Ag1+ Silver ion

Cd2+ Cadmium ion

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Transition Metals (Group 3-12) may have more than one oxidation state.

The oxidation state of the transition metal is indicated by a Roman numeral in parenthesis after the metals name (e.g., copper(I) ion is Cu1+).

This is important: Iron(III) DOES NOT mean Fe3, it means Fe3+.

Determining the charge on the transition metal means you have to know the names and charges of anions.

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Monoatomic anions take the root of the element and add “-ide” (i.e., Cl1- is chloride, O2- is oxide).

Halogens (Group 17), when combined with metals, always form a negative 1 charged ion but may form positive oxidation states when combined with oxygen and other non-metals.

Chalcogens (Group 16), when combined with metals, always form a negative 2 charged ion (O2-, S2-, Se2-).

Group 15, when combined with metals, always form a negative 3 charged ion (N3-, P3-, As3-).

Group 14, when combined with metals, always form a negative 4 charged ion (C4-, Si4-).

Hydrogen, when combined with metals, always form a negative 1 ion (H1-) When combined with non-metals will form a plus 1 ion (H1+) .

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The ion with the most oxygen atoms takes the suffix –ate following the root of the first element (i.e., nitrate for NO3

-). The ion with the least oxygen atoms

takes the suffix –ite following the root of the first element (i.e., nitrite for NO2

-). Other examples:

SO42- Sulfate SO3

2- Sulfite

PO43- Phosphate PO3

3-

Phosphite

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Other important polyatomic oxygen containing ions:

Carbonate CO32-

Oxalate C2O42-

Acetate C2H3O21-

Manganate MnO42−

Permanganate MnO41−

Chromate CrO42−

Dichromate Cr2O72-

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The ion with the most oxygen's takes the suffix –ate following the root of the first element (i.e., chlorate for ClO3

-). The ion with the least oxygen's takes the suffix –ite

following the root of the first element (i.e., chlorite for ClO2

-). The ion with the one more oxygen than the –ate

ion takes the prefix per before the root of the first element and the suffix –ate following the root of the first element (i.e., perchlorate for ClO4

-). The ion with one less oxygen than the –ite ion

takes the prefix hypo before the root of the first element and takes the suffix –ite following the root of the first element (i.e., hypochlorite for ClO-).

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Diatomic Acids Halogen containing acids:

These acids are named by adding hydro before the root of the halogen, adding –ic after the root, and adding acid

HF(aq) Hydrofluoric acid HCl(aq) Hydrochloric acid HBr(aq) Hydrobromic acid HI(aq) Hydroiodic acid

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The acid with the most oxygen's takes the suffix –ic following the root of the first element (i.e., chloric for HClO3) and adding acid. For HClO3 the name is chloric acid.

The acid with the least oxygen's takes the suffix –ous following the root of the first element (i.e., chlorous for HClO2) and adding acid. For HClO2 the name is chlorous acid.

The acid with the one more oxygen than the –ic acid takes the prefix per before the root of the first element and the suffix –ic following the root of the first element (i.e., perchloric for HClO4) and adding acid. For HClO4 the name is perchloric acid.

The acid with one less oxygen than the –ous acid takes the prefix hypo before the root of the first element and takes the suffix –ous following the root of the first element (i.e., hypochlorous for HClO). For HClO the name is hypochlorous acid.

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The acid with the most oxygen's takes the suffix –ic following the root of the first element and adding acid. Nitrate forms HNO3(aq) nitric acid Sulfate forms H2SO4 (aq) sulfuric acid Phosphate forms H3PO4 (aq) phosphoric acid

The acid with the least oxygen's takes the suffix –ous following the root of the first element and adding acid. Nitrite forms HNO2 (aq) nitrous acid Sulfite forms H2SO3 (aq) sulfurous acid Phosphate forms H3PO3 (aq) phosphorous acid

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Carbonate ion forms H2CO3 (aq) Carbonic acid

Oxalate ion forms H2C2O4 (aq) Oxalic acid

Acetate ion forms HC2H3O2 (aq) Acetic acid

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Hydrates are ionic compounds with loosely bound water molecules.

Examples:- MgSO4·2H2O, magnesium sulfate

dihydrate

MgSO4·7H2O, magnesium sulfate heptahydrate (epsom salts)

Na2CO3·10H2O, sodium carbonate decahydrate (washing soda).

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The number of water molecules is given by Greek prefixes:

Incorrect examples:MgSO4-2H2O

Magnesium diwater

Magnesium di(dihydrogen oxide)

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Molecular (or covalent) compounds consist of two non metal elements.

Prefixes are used to indicate the number of atoms.

The less electronegative element is named first in covalent compounds.

The name of the second nonmetal ends in –ide. Some nonmetals can form more than one

compound. Mono is never used if there is only 1 atom of

the first nonmetal.

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STEP 1 Name the first nonmetal by its element name. STEP 2 Name the second nonmetal with an ide

ending.STEP 3 Prefixes to indicate the number (from

subscripts) of atoms of each nonmetal. Mono is usually omitted.

Name P4S3

STEP 1 The first nonmetal P is phosphorus. STEP 2 The second nonmetal S is sulfide.STEP 3 The subscript 4 of P is shown as tetra.

The subscript 3 of O is shown as tri.

P4S3 → tetraphosphorus trisulfide18

Other Examples: Phosphorus pentachloride:1P penta = 5Cl

PCl5

Dinitrogen trioxide:di = 2N tri = 3 ON2O3

Xenon tetrafluoride:1Xe tetra = 4F

XeF4

Write the formula for carbon disulfide.

STEP 1 Elements are C and SSTEP 2 No prefix for carbon means

1 C Prefix di = 2 means 2

S Formula: CS2 19

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Identify each compound as ionic or molecular, and give its correct name:

A. SO2 molecular: 1 S, 2 O sulfur dioxide

B. BaCl2 ionic: Ba2+, Cl− barium chloride

C. N2O4 molecular: 2 N, 4 O dinitrogen tetroxide

D. Cu2CO3 ionic: copper(I) carbonate

E. Ca3(PO4)2 ionic: Ca2+, PO43−

calcium phosphate

F. FeBr3 ionic: Fe3+, Br − iron(III) bromide

G. SCl2 molecular: 1 S, 2 Cl sulfur dichloride

H. Cl2O molecular: 2 Cl, 1 O dichlorine oxide

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