# Which of the following is not a permissible arrangement of electrons in an atom? Option 1) $n=5,l=3,m=0,s=+1/2$ Option 2) $n=3,l=2,m=-3,s=-1/2$ Option 3) $n=3,l=2,m=-2,s=-1/2$ Option 4) $n=4,l=0,m=0,s=-1/2$

D Divya Saini

As learnt in

Magnetic Quantum Number (m) -

For any sub-shell (defined by ‘l ’value) $2\: l+1$values of m are possible and these values are given by :

m = – l , – ( l –1), – ( l – 2)... 0,1... ( l – 2), ( l –1),l

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$\therefore$ for l=2, m can have -2, -1, 0, 1, 2 as possible values and not -3.

Option 1)

$n=5,l=3,m=0,s=+1/2$

This solution is incorrect

Option 2)

$n=3,l=2,m=-3,s=-1/2$

This solution is correct

Option 3)

$n=3,l=2,m=-2,s=-1/2$

This solution is incorrect

Option 4)

$n=4,l=0,m=0,s=-1/2$

This solution is incorrect

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