Question

The maximum number of electrons that can be present in the third shell having ms value=+1/2 is??

Answer 1

We know that -

The maximum number of electrons present in any she'll can be found using the rule ,

2n²

Where , n represents the number of the shell .

Here , In the third shell -

Total number of electrons found in the third shell -

=> 2 × 3²

=> 2 × 9

=> 18 electrons .

Now , for spin value of +½ , number of electrons -

=> ½ × ( Total number of electrons )

=> ½ × 18

=> 9 electrons -

.Thus , we can conclude that -

Number of electrons found in the third shell with ms value = +½ is 9 .

This is the required answer .

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Answer 2

Explanation:

Depends what subshell you’re talking about.

The subshells (s, p, d, etc) have specific Azimuthal values (often denoted by ‘l’).

The number of orbitals a subshell can contain = 2l + 1

So let’s suppose we’re talking about the p subshell. The p subshell has l=1.

So the number of orbitals it contains = 2(1) + 1 = 3.

So our p subshell has 3 orbitals. And according to Pauli’s Exclusion Principle, each orbital can contain at most TWO electrons.

So in essence, the p subshell contains 3*2=6 electrons in all.

But again, according to Pauli’s Exclusion Principle, no two electrons can have the same set of four quantum numbers. So in each orbital, there would be one electron with a +1/2 spin, and one with a -1/2 spin.

Long story short, half of the total electrons contained in the subshell will have spin +1/2, and the other half spin -1/2.

So the number of electrons in the p subshell with ms +1/2 = 1/2* of 6 = 3.