Question

Question #e207f

Answer 1

An ion is an atom with a positive or negative charge due to the loss or gain of electrons.

All atoms try to complete the valence orbitals and complete the rule of octet. In order to accomplish this, atoms will give up electrons or gain electrons.

Magnesium has an electron configuration of `1s^2 2s^2 2p^6 3s^2`
The valence shell in this case is the highest energy level `3s^2`. In order to complete the rule of octet the magnesium atom can either lose 2 electrons or try to gain 6. Since it easier to lose 2, the atom gives up two electrons. The atom now has 12 protons but only 10 electrons. With 2 more protons than electrons the charge on the atom is +2. The Magnesium is now a `Mg^(+2)` cation.

Fluorine has an electron configuration of `1s^2 2s^2 2p^5`
The valence shell in this case is the highest energy level `2s^2 2p^5`. In order to complete the rule of octet the fluorine atom can either gain 1 electrons or try to lose 7. Since it easier to gain 1, the atom takes on 1 electron to fill the outer shell. The atom now has 9 protons and 10 electrons. With 1 more electron than protons the charge on the atom is -1. The Fluorine is now a `F^(-1)` anion.

Here is a video which discusses how ions form and how to determine their charges.

Video from: Noel Pauller

I hope this was helpful.
SMARTERTEACHER