Nomenclature Ionic Compounds. Learning Goals We are learning to – Name ionic compounds – Understand the charges of ions in ionic compounds – Use what.

NomenclatureIonic

Compounds

Learning Goals

• We are learning to – Name ionic compounds – Understand the charges of ions in ionic compounds– Use what we know

about ionic charge todetermine chemicalformulas

– Name ionic compounds containing polyatomic ions

Ionic Compounds

Recall: • An ionic compound is formed from one or

more positively charged ions and one or more negatively charged ions

• In ionic bonding, electrons are transferred from one atom to another.

• The oppositely charged ions are attracted to each other by electrostatic forces, which are the basis of the ionic bond.

Ionic Bonding

• Metals lose electrons, become positively charged – sodium, potassium, magnesium, calcium

• Non-metals gain electrons, become negatively charged– chlorine, silicon, oxygen, sulphur

• The result of bonding is a compound that has an overall neutral charge

Drawing Chemical Symbols

• When a sodium atom loses one electron and becomes a positively charged ion it is symbolized as: Na+ to indicate a charge of +1– When more than one electron is exchanged the

number is placed before the charge. – sulfur gains 2 electrons is symbolized as S2-

• What about the following elements?– chlorine gains 1 electron– calcium loses 2 electrons– oxygen gains 2 electrons– aluminum loses 3 electrons

Ionic Formula

• The formula of an ionic compound is derived by combining ions such that a neutral compound is created

• Let’s try some examples:– calcium and chlorine– magnesium and oxygen– lithium and bromine– magnesium and nitrogen

Naming Ionic Compounds

1. Name the metal ion first – same as element name• In KBr the name of the K+ ion is potassium.

2. Name the non-metal ion second. When non-metal becomes a negative ion, the ending of its name changes to “ide”• A bromine atom gains an electron to become a bromide ion

3. Combine the names• The name of KBr is potassium bromide

Naming Ionic Compounds

• Let’s try some examples:– calcium and chlorine– magnesium and oxygen– lithium and bromine– magnesium and nitrogen

Naming Ionic Compounds

• Some metals are able to form more than one kind of ion– EXAMPLES: copper, lead, iron, nickel

• Roman numerals are used to indicate ionic charge– EXAMPLE: There are two types of copper ions: Cu+

and Cu2+

• Copper(I) chloride: Cu+ forms the compound (CuCl)• Copper(II) chloride: Cu2+ forms the compound (CuCl2)

Naming Ionic Compounds

• You can determine the Roman Numeral to use in the name of a multivalent ion from the subscripts in the compounds formula.– EXAMPLE: CrCl3

– Chlorine holds a charge of -1 and there are 3 of them in the chemical formula, therefore to make the molecule neutral the chromium must have a charge of +3.

– Name is chromium(III) chloride

Naming Ionic Compounds

• Let’s try some examples:– FeCl2

– FeCl3

– CuN2

– Ni2O3

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