Question

if nitrogen has a valency of 3 then why when it is combined with hydrogen the valency of nitrogen is written as 2​

Answer 1

Answer:

Allied solutions

Grade 8

Chemistry

Chapters in Simplified Middle School Chemistry - Class 8

Exercises in Language of Chemistry

Question 2

Q2) Define the term ‘valency’. With reference to water & ammonia as compounds respectively, state the valency of oxygen & nitrogen. Magnesium [[2, 8, 2]] has valency 2+. Give reasons.

Solution

Transcript

Solution:

Valency is the number of particular atoms combined with or displaced with another atom to form a compound.

Water which is H_2

2

O, two atoms of hydrogen combine with one atom of oxygen. The valency of oxygen is 2, because it needs two atoms of hydrogen to form water.

Ammonia which is NH_3

3

, One atom of nitrogen combines with 3 atoms of hydrogen. The valency of nitrogen is 3 because it needs 3 atoms of hydrogen to form ammonia.

Magnesium has valency equal to 2^+

+

because the electronic configuration of Mg is [2,8,2]. The nearest noble gas to magnesium is neon with electronic configuration of [2,8], to achieve this stable electronic configuration Mg can lose 2 valence electrons, hence its valency is 2^+

+

.