Naming Ionic Compounds

Transition Metals and Polyatomic ions

Remember:

• No prefixes !!!!!!

1. Write the name of the metal.2. Write the name of the non-metal.3. Change the ending of the non-

metal to “ide”Ex: NaCl sodium chloride

Transition Metals:• Nearly all the transition metals are

able to form more than one cation or are multi-valent.

• Ex: iron can form Fe2+ and Fe3+. Given the formula of an ionic compound you can use the reverse cross-over method to determine the charge of the cation. Ex: FeCl3

Stock System:

• The charge of the cation is written in parentheses as a roman numeral. Ex: Fe3+ would be iron (III) and Fe2+ would be iron (II).

• Remember roman numerals: 1-(I), 2- (II), 3-(III), 4-(IV), 5-(V).

Example:• Both CuO and Cu2O are real compounds• We know that O always has a charge of

-2

• For CuO, we know that it is the Cu+2 ion (sum to zero)

copper (II) oxide

• And for the Cu2O, we know that there is 2 x the Cu+1 ion (to sum to zero)

copper (I) oxide

Try to write names for these (don’t forget the roman numberial for the metal) :

• CrO

• Au3P

• SnCl4

Given the name we can write the formula:• Nickel (III) bromide• We know that Br is always Br-1

• We also know that this is the Ni3+ ion (it tell us in the brackets)

• Therefore we need 3 x Br-1 with Ni3+ for the compound to be neutral (sum

to zero) NiBr3

Try these:

• lead (II) chloride

• mercury (I) arsenide

• cobalt (II) chloride.

Polyatomic Ions

• Have a charge ( + or - )• Consists of two or more non-metal

atoms (or metal complex) joined by a covalent bond

• Act as a single unit

Write names for ionic compounds containing polyatomic ions:

• Na2CO3

• KOH

• Sn3(PO4)4

Writing chemical formulas for ionic compounds containing polyatomic ions: (remember to use parentheses to indicate the correct number of ions)

1. ammonium sulfide

2. lead (IV) hydrogen carbonate

3. calcium hydroxide

4. magnesium nitrate

Practice: handout