Question

how will you find valency of chlorine sulphur and magnesium

Answer 1

Atomic number of chlorine= 17
configuration= 2,8,7
hence, valency is 1

sulphur = 16
configuration = 2,8,6
valency is 2

Magnesium = 12
configuration = 2,8,2
valency is 2

Answer 2

Answer:

Cl(17) has 17 electrons. It's electronic configuration is 2, 8, 7. It can gain electron to become stable like noble gas argon, so, it's valency is equal to 1.

S(16) has 16 electrons. It's electronic configuration is 2, 8, 6. It can gain 2 electrons to become stable like noble gas argon, so, its valency is 2.

Mg(12) has 12 electrons. It's electronic configuration is 2, 8, 2. It can lose 2 electrons to become stable like noble gas neon, so, its valency is equal to 2.