Question

1 and 2 are electrovalencies of chlorine and magnesium respectively. why?​

Answer 1

The valency of an element depends upon the number electrons it can lose or gain in its outermost shell . As chlorine has 7 electrons in its outermost shell, in order to attain a stable electronic configuration to its nearest noble gas (i.e, argon) it tends to gain one electron hence showing a valency of 1- . In the same way magnesium has 2 electrons in its outermost shell, so in order to attain a stable electronic configuration to its nearest noble gas (i.e, neon) it tends to lose two electrons hence showing a valency of 2+ .

Explanation:

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