Inorganic nomenclature Nomencalture

Writing Formula of Ionic Compounds Formula is representation of the composition of a substance showing the symbol of the elements and the number of atoms of each elements in the compound. Ionic compounds are compounds of metals and non-metals Formula of ionic compound shows the ratio of ions The ratio will always be in lowest terms. The charges on ions must balance to become neutral

Metals and Non-metals Lithium oxide Find both elements in the periodic table, write symbol of ions with charges Add either positive or negative ions (or both) to balance out the charges

Now write the formula to show how much of each element is needed to balance out the charges Potassium Nitride

Ionic compounds with Polyatomic Ions Calcium Nitrate

Metals with more than one combining capacity If metal has more than one combining capacity, we are told in the chemical name Lead(ll)oxide Lead(lV)oxide

Writing names of ionic compounds Write the name of metal first and non-metal ion second. For simple ionic compounds, change non-metal ending to IDE NaBr-------------- Al2 O3

Write names of ionic compounds with more than one combining capacity If a metal has more than one combining power, you must show the combining power with a roman numeral Start with the ion which we do know. Work backward to know the charge of metal ion FeCl3

PbO PbO2

Polyatomic Ions Polyatomic ions: do not change ending of ion NaNO3 NH4 HCO3

Hydrates Hydrate: an ionic salt that has water associated with it ( in its crystalline form) e.g. CuSO4 . 5H2 O each formula unit of copper sulphate has 5 water molecules attached to it Named just like ionic compounds, except… – the Greek prefixes are added at the end with the word “hydrate” to show how many water molecules are present

Greek Prefixes Prefixes used No. Of water molecules mono hexa di hepta tri octa Tetra nona penta deca

Zn (CH3CHOO) 2 .2 H2O Ni3 (PO4)2 . 8H2 o

Iron(II)Phosphate octahydrate Aluminum nitrate nonahydrate:

Covalent Bonds To write the formula of a covalent bond, the most metallic element usually goes first The formula tells us what is in a molecule of the compound so it is not reduced to the lowest term The first word is just the name of the first element with a prefix ( mon, di, tri, tetra, etc)

Prefixes tell us how many of each atom are present in a molecule When naming covalent compounds mono is not needed in the first element name Name of second element ends in ide Example: ICI S4N2

BrF P2O6

Tetraphosphorus trisulphide Trisilicon tetranitride Oxygen difluoride