writing ionic formulae

Question 1

when are ionic compounds formed

Answer 1

Ionic compounds are formed form a positive ion (usually a metal) and a negative ion (usually a non-metal).

Question 2

4 rules of writing ionic formulae

Answer 2

1. The positive ion is written first.
2. The negative ion is written second (non-metal
   or group of non-metals).
3. The total number of each ion is adjusted so
   that the total positive charge equals the total
   negative charge.
4. Subscripts are used to indicate the number of
   each ion present.

Question 3

what are polyatomic ions

Answer 3

atoms that are formed from a small group of atoms and have an overall charge is known as polyatomic ions

Question 4

Carbonate

Answer 4

CO3 2-
1x Carbon
3x Oxygen
2- charge

Question 5

Sulfate

Answer 5

SO4 2-
1x Sulfer
4x Oxygen
2- charge

Question 6

Hydroxide

Answer 6

OH 1-
1x Oxygen
1x Hydrogen
1- charge

Question 7

Phosphate

Answer 7

PO4 3-
1x Phosphurus
4x Oxygen
3- charge

Question 8

Ammonium

Answer 8

NH4 1+
1x Nitrate
4x Hydrogen
1+ charge

Question 9

how do polyatomic ions compound

Answer 9

Polyatomic ions form ionic compounds the same way monatomic (single) ions do.

Question 10

5 rules of writing ionic formulae with polyatomic ions

Answer 10

1. The positive ion is written first.
2. The negative ion is written second.
3. The total number of each ion is adjusted so
   the total positive charge equals the total
   negative charge.
4. Subscripts are used to indicate the number of
   each ion present.
5. When there is more than one polyatomic ion,
   brackets are needed around the ion.