Question

just answer no. 15 . please

Answer 1

$\mathfrak{\huge{Answer:-}}$

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Electronic Configuration - ( 2 , 8 , 7)

Group Number - 17

Period Number - 3

Number of Valence electrons - 7

Valency - 1

The element is a NON - METAL

Number of Protons - 17

Number of Nuetrons - (35-17) = 12

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