This document discusses valency and variable valency in chemistry. It defines valency as the combining capacity of an element or radical. It then lists the valencies of some common elements and radicals. The document explains that elements showing more than one valency exhibit variable valency, like iron which can be +2 or +3. It describes how lower and higher valencies are denoted, either by adding suffixes like "-ous" and "-ic", or using roman numerals in brackets. Finally, it gives examples of common elements that exhibit variable valency, such as copper, silver, and iron.

1. THE LANGUAGE OF
CHEMISTRY
- Valencyandvariable valency

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VALENCY
Definition: The combining capacity of an element or of
a radicalis known as valency.
Valencycan be 0,1,2,3 etc.,

3. S.No. Name of the element Symbol Valency
1. Hydrogen H 1
2. Helium He 0
3. Carbon C 4
4. Nitrogen N 3
5. Oxygen O 2
6. Fluorine F 1
7. Neon Ne 0
8. Sodium Na 1
9. Magnesium Mg 2
10. Aluminium Al 3
11. Argon Ar 0
VALENCIES OF SOMEELEMENTS

4. VALENCIES OF SOMERADICALS
NAME OF THE RADICAL SYMBOL VALENCY
Sodium Na+
1
Potassium K+
1
Ammonium NH4
+
1
Magnesium Mg2+
2
Calcium Ca2+
2
Zinc Zn2+
2
Aluminium Al3+
3
Hydroxide OH-
1
Chloride Cl-
1
Carbonate CO3
2-
2
Sulphate SO4
2-
2
Nitride N3-
3
Phosphate PO4
3-
3

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VARIABLE VALENCY
Definition: Elements showing morethan one valencyis
known as variable valency.
Eg: Ironexhibitthe valencies2 and 3
 Copper exhibitthe valencies 1 and 2

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HOW TO DENOTE
VARIABLE VALENCY?
For lowervalency,the suffix‘ous’ should be added to
the name of the element
Eg: Iron is named as ‘Ferrous’ when it exhibits the
valency2. (lowervalency)

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HOW TO DENOTE
VARIABLEVALENCY?
For highervalency,the suffix‘ic’ should be added to the
name of the element
Eg: Iron is named as ‘Ferric’when it exhibits thevalency
3. (highervalency)

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HOW TO DENOTE
VARIABLE VALENCY?
Insteadof using suffixes,roman numeralscan also be
used.
The valencyis represented in roman numeralsenclosed
in brackets
Eg: ‘Ferrous’ is represented as Iron(II)and‘Ferric’as
Iron(III)

9. VALENCIES OF SOMERADICALS
NAME OF THE
ELEMENT
SYMBOL LOWER VALENCY STATE HIGHER VALENCY STATE
Copper Cu Cu+ or Cu(I)
Copper(I)/ Cuprous
Cu2+ or Cu(II)
Copper(II)/ Cupric
Silver Ag Ag+ or Ag(I)
Silver(I)/ Argentous
Ag2+ or Ag(II)
Silver(II)/ Argentic
Iron Fe Fe2+ or Fe(II)
Iron(II)/Ferrous
Fe3+ or Fe(III)
Iron(III)/Ferric
Lead Pb Pb2+ or Pb(II)
Lead(II)/ Plumbous
Pb4+ or Pb(IV)
Lead(IV)/ Plumbic

10. Chemicalequations
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