Q10 of 58 Page 1

The atomic number of an element is 17. Predict (a) its valency, (b) whether it is a metal or non-metal, (c) its relative size with respect to other members of its group. Justify your answer in each case.

Given: Atomic no. of element = 17

Electronic configuration: 2, 8, 7


(a) Since it requires one more electron to complete its stable gas configuration, so the valency is 1.


(b) This is a non-metal because it will acquire stability after gaining one electron and those who gain electrons are non-metals.


(c) Since this element is the second member of its group, so, the size will be greater than the first member but as we know from top to bottom, size decreases. So the size will be smaller for other elements.


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