NOMENCLATURE

HOW DO I KNOW THE ION FORMED BY VARIOUS ELEMENTS?

The periodic table group numbers signify the number of valence electrons members of that group each have.

The valence electron number will indicate whether or not that element/group will lose or gain electrons, and how many Groups 1-3 and the transition elements lose

electrons to become positive ions Groups 5-7 gain electrons to become negative

ions Group 4 and 8 do not form ions

THE PERIODIC TABLE AS A USEFUL TOOL

NAMING BASICS: IONIC COMPOUNDS

Ionic compounds are formed between a metal and a nonmetal Metals: groups 1, 2, 3, & the transition metals

(short rows) Nonmetals: primarily groups 5, 6, & 7

To name them: Cation + Anion + ide Cation: positive ion Anion: negative ion Na + Cl = Sodium Chloride

DETERMINING THE MOLECULAR FORMULA OF AN IONIC COMPOUND

Compounds are by definition neutral. When combining ions to form an ionic compound, the overall charge of the compound must equal zero

Subscripts are used to indicate the number of each element needed in order to have a neutral compound

For example: Na + Cl = NaCl (+1, -1 equals zero) Mg + Br = MgBr2 (+2, -1, -1 equals zero)

COMPOUND WITH POLYATOMIC IONS

Polyatomic ions are groups of atoms that act together as one unit

COMPOUNDS WITH POLYATOMIC IONS

When naming compounds with polyatomic ions, use the name of the polyatomic ion with no –ide suffix

For example: K2S = Potassium sulfide while K3PO4 = Potassium phosphate

In the example above, the rules for determining subscripts remains the same: the goal is for the compound to be neutral (no electrical charge)

K = +1 charge, PO4 = -3 charge and so I will need three K+ ions to bond with one PO4 polyatomic ion in order to reach an electrical charge of zero (neutral

COMPOUNDS WITH ELEMENTS THAT FORM MORE THAN ONE TYPE OF ION (MULTIPLE CHARGES)

When naming a compound containing an element that can form more than one type of ion, a Roman numeral is used to indicate the charge of that ion in that particular compound

Copper (II) Oxide: Copper has a +2 charge, and therefore the formula will be CuO

Copper (I) Oxide: Copper has a +1 charge and therefore the formula will be Cu2O

COMMON TRANSITION ELEMENTS WITH MORE THAN ONE ION FORMATION

NAMING COMPOUNDS CONTAINING ONLY NONMETALS

When nonmetals combine, the naming system is different. Because you cannot necessarily use the PT to

indicate the quantities of each atom in the compound, the name must indicate the amounts using standard prefixes: mono, di, tri, tetra, penta, hexa, hepta, octa, nona, and deca

The only time a prefix is not used is for the first element of the name when there is only one of that element in the compound. CO carbon monoxide N2O4 dinitrogen tetraoxide