Question

3.A student writes the arrangement of electrons in an atom as 2, 10, 1. Why is this wrong? What should the student have written?​

Answer 1

Answer:

It is wrong because the maximum number of electrons that can be accommodated in the outermost shell is 8.

Step-by-step explanation:

The maximum number of electrons in a shell is 2n^2 where n is the number of shell

i. e. if we write electronic configuration of Sodium

Na=2,8,1

in first shell there is 2 electrons because 2n^2=2*(1)^2=2*1=2

like that in second 2*(2)^2=2*4=8

in third 2*(3)^2=2*9=18

but since it is sodium whose atomic number is 11 so in third only one electron

from third shell onwards the maximum number of electrons that can be accommodated is 8

Now, the student should write the electronic configuration like this:

since sum of electrons is 13

So, it is Aluminum

Therefore, Al =2,8,3

Hope this will help you.....

Thank you....