Question

He:K shell::AR:?
pls tell​

Answer 1

$\boxed{ \bold{He:K \: shell :: Ar: M \: shell}}$

But why ?

• He has atomic number 2 , so it's electronic configuration is :

$\rm \: He_{2} : 1 {s}^{2}$

• Its valence electrons are present in the K shell.

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• Now, for Argon with atomic number 18, electronic configuration is:

$\rm Ar_{18} : 1 {s}^{2} \: {2s}^{2} \: {2p}^{6} \: \boxed{ \rm{3s}^{2} \: {3p}^{6} }$

• So, 8 valence electrons are present in M shell.

So, answer will be M shell, as shown above !