Question

What is the electronic configuration of an element with atomic number 17? Also tell its valency.......This question came in my exam for 2 marks. I have written rhe correct valency...but the electronic configuration that i have done is...2,8,8,7.....I wrote two 8s by mistake....How many marks will be deducted??

Answer 1

1s2,2s2,2p6,3s2,3p5 = electronic configuration of chlorine
it has 7 valence electron in outer shell so it need 1 electron it's valency is -1
I think only 1 mark will be deducted

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