Question

Class
Chemistry Common Notes
Ind N shells. Which of these is/are incomplete?
Calcium has twenty electrons which occupy K.L.Mand N shells. Which 01
A
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Answer 1

Answer:

Explanation:

Label each shell as n=1, n=2, etc.

Each shell can contain  2 n 2  electrons

The first shell holds 2 electrons. We have 18 electrons left.

The second shell holds 8 electrons. 10 electrons left.

The third shell is able to hold 18 electrons.

However, the third shell only holds 8 electrons before the fourth shell starts to fill. The third shell carries on filling up only after 2 electrons are in the 4th shell. So what happens in calcium is that 8 of the remaining 10 electrons are in the 3rd shell, and the other 2 are in the 4th shell.

Number of electrons in outermost shell ( 4 th  shell) is 2

no shell is incomplete