What is the electron configuration when the valence electrons are removed from each of the elements listed in the chart?

The answer to your question is given below.

Explanation:

Data obtained from the question include:

Sodium, Na => 1s2 2s2 2p6 3s1

Magnesium, Mg => 1s2 2s2 2p6 3s2

Aluminium, Al => 1s2 2s2 2p6 3s2 3p1

Sodium has 1 valence electron. If we remove the valence electron, sodium metal will become an ion. Thus, the electronic configuration becomes

1s2 2s2 2p6.

Magnesium has 2 valence electrons. If we remove the valence electrons, magnesium metal will be an ion. Thus, the electronic configuration becomes

1s2 2s2 2p6.

Aluminium has 3 valence electrons. If we remove the valence electrons, aluminum metal will become an ion. Thus, the electronic configuration becomes

1s2 2s2 2p6.