Question

Question #99793

Answer 1

General formula: `ns^2np^2`

n means energy level or shell (which is numerically equal to periods or rows of the periodic table)

Explanation:

Some examples of atoms with 4 valence electrons include carbon, silicon and germanium.

So, let's write the electron configurations of each of these atoms
(in the order of energy levels);

C: `1s^2* 2s^2*2p^2`

Si: `1s^2*2s^2*2p^6*3s^2*3p^2`

Ge: `1s^2*2s^2*2p^6*3s^2*3p^6*3d^10*4s^2*4p^2`

As you can see, the last two subshells (or "terms") in each atom have that general formula.
Hope this helps!