Question

The electronic configurations of three elements X, Y and Z are X — 2, 8; Y — 2, 8, 7 and Z — 2, 8, 2. Which of the following is correct? A Y is a non-metal and Z is a metal B Z is a non-metal C Y is a metal D X is a metal

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Answer 1

Answer:

A

Explanation:

The configuration of Y is 2,8,7 so according to class 9 standard if we add then atomic no. is 17 which is actually Chlorine (Cl, a non metal) and likewise Z is Actually Magnesium(Mg, a metal)

For 11th standard this can be explained in another way