ICSE Class 7 Answered

Representation of some positive radicals and their valency

Name of Radical	Representation	Valency
Hydrogen	H+	1
Sodium	Na+	1
Potassium	K+	1
Silver	Ag+	1
Ammonium	NH4+	2
Magnesium	Mg2+	2
Calcium	Ca2+	2
Iron(II)	Fe2+	2
Gold	Au2+	2
Copper(II)	Cu2+	2
Iron(III)	Fe3+	3
Aluminium	Al3+	3
5Platinum(IV)	Pt4+	4

Representation of some negative radicals and their valency

Name of Radical	Representation	Valency
Chloride	Cl−	1
Bromide	Br−	1
Hydroxide	OH−	1
Acetate	CH3COO−	1
Nitrate	NO3−	1
Nitrite	NO2−	1
Bisulphate	HSO4−	1
Bisulphite	HSO3−	1
Bicarbonate	HCO3−	1
Oxide	O2−	2
Carbonate	CO32−	2
Sulphate	SO42−	2
Sulphite	SO32−	2
Dichromate	Cr2O72−	2
Nitrite	N3−	3
Phosphate	PO43−	3

 

 

Step-by-step method for writing a chemical formula: