Question

write the Electronic configuration of Element with atomic number 20 Indicate the valency of an atom.
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Answer 1

Explanation:

Atomic number 20 is of Calcium -

Electronic configuration – 1s2 2s2 2p6 3s2 3p6 4s2.

Group - It belongs to second group.

Period – It belongs to 4th period.

Valency – Valency of calcium is +2