Question

The first eight ionization energies of a third row element are 999.6, 2252, 3357, 4556, 7004, 8496, 27107, and 31719 kJ/mol. Identify the element.

Choose one:A. AlB. SC. MgD. PE. NaF. ArG. ClH. Si

Answer 1

As you can see from the ionization energies given, there is a huge difference between the 6th ionization energy and the 7th ionization energy.

$\Rightarrow$ The atom is stable when 6 electrons are taken out of it. That is why the 7th ionization energy is so high. It is more than 3 times of the 6th ionization energy.

This suggests that the atom has 6 valence electrons. Since when 6 electrons are taken out of it, it attains a stable configuration.

In the third row, sulfur has 6 valence electrons.

Option B is the right answer