Question

The electronic configuration of an element A is 2, 8, 7. (5)

( i). What is the group number of A?

( ii). What is the period number of A?

(iii). How many valence electrons are there in an atom of A?

(iv). What is the valency of A?

(v). Is it a metal or a non-metal?
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Answer 1

Answer:

Group = 17 (chlorine)

Period = 5 as last shell has 5 electrons

Valence electrons = 1

Non- metal

Answer 2

Answer:

I)group 17,VIIB

ii)3

iii)7

iv)-1

v)non-metal