how many electrons are in this atom? energy

Explanation:

Step1: Count electrons in 1s

The 1s orbital has 2 electrons.

Step2: Count electrons in 2s

The 2s orbital has 2 electrons.

Step3: Count electrons in 2p

The 2p orbital has 6 electrons (3 sub - orbitals with 2 electrons each).

Step4: Count electrons in 3s

The 3s orbital has 2 electrons.

Step5: Count electrons in 3p

The 3p orbital has 5 electrons (2 in two sub - orbitals and 1 in the third).

Step6: Sum up electrons

$2 + 2+6 + 2+5=17$

Answer:

17