Question

If an atom has twelve electrons, how many electrons are in the n=1 energy level? How many electrons are in the n=2 energy level? How many electrons are in the n=3 energy level?
n=1 shell ?
n=2 shell ?
n=3 shell ?

Please help me!

Answer 1

If an Atom has 12 Electrons then if it is a Neutral atom then the Atomic Number of the Atom will be 12.

The Electronic Configuration of Element with Atomic Number 12 will be :

⇒ 1s² 2s² 2p⁶ 3s²

We can notice from the Electronic Configuration that :

Given atom has 2 electrons in the 1st shell.

⇒ In the Shell : n = 1

   Number of Electrons = 2

In the similar way : Number of Electrons in 2nd shell = 2 + 6 = 8

⇒ In the Shell : n = 2

   Number of Electrons = 8

In the similar way : Number of Electrons in 3rd shell = 2

⇒ In the Shell : n = 3

   Number of Electrons = 2