Question

how to find the valency of so4

Answer 1

SO4 has a valency of 2 . To find its valency ,I can advice you 2 ways which I often use are:
a•SO4 is an anion which has came from an acid H2SO4, in which hydrogen as always has valency 1. Since hydrogen is more electro+ve than SO4,its oxidation no. will be +1. So by using this information we can find oxidation no. of SO4.

Let x be oxidation no. of SO4. Since, the sum of oxidation nos. will be zero, so equating it with zero:

2×H+1×SO4=0

2×1+1×x=0

x=-2Which is the oxidation no. of SO4.

This implies that it has valency 2.

Note: Remember Valency is combining capacity ,it does not have +or - charge, while oxidation no. show whether it can gain(+ve charge) or lose (-ve charge) electrons.

b• Sulphur has 6 electrons in its Valence shell& oxygen has a oxidation no. -2 so when 4 oxygens combine with 1 Sulphur , the octet of the Sulphur is extended by by 2 more electrons(Sulphur has 6 electrons & 4Oxygens gives it 8 electrons i.e., 2 more electrons) which gives SO4 a oxidation no. Of -2 & valency

Answer 2

Valency of SO4 = 2

Explanation:

Valency of an element is its tendency to give away electrons. So we have to look at the number of electrons on its outermost shell.

To get valency of SO4, let us consider valency of sulphur and oxygen. Sulphur has 6 electrons in its outer shell. Oxygen has a oxidation no. -2, for four oxygen atoms, we have oxidation number of -8. Now for the combined molecule, the octet of the Sulphur is extended by 2 more electrons. So oxidation number of SO4 is -2.