Question

5. 4s2 is the configuration of
the outermost orbit of
an element. Its atomic number would be :-
(1) 29 (2) 24 (3) 30 (4) 19​

Answer 1

Answer:

20

Explanation:

1s2; 2s2, 2p6; 3s2, 3p6; 4s2

Counting all the electrons we get 20. So, 20 will be the answer.

Kindly, check the question or option again if 20 is not in the option then make it.

Answer 2

Answer:

2) 30 is the answer with 4s2 3d10

Explanation:

Argon is nearest of above options...with 3s2 3p6 is it's outer most orbital configuration..

• next orbital according to af bous law is 4s2 3d9 but by LAW OF HUNDS it's configuration is
• 4s1 3d10 (18+11=29 electrons)
• next Zinc is having 4s2 3d10 it's outer most orbital configuration