Question

3.Why does an atom of Mg form a di positive ion and an
atom of Oxygen form a di negative ion during chemical
reaction?

Answer 1

Answer:

All metals hate electrons or you can say they easily give off their valence electrons but this is totally opposite in the case of non metals.They don't give off their valence electrons easily. They gain electrons to get to their noble state.

-As Magnesium is a metal it will lose electrons. Electronic Configuration of Mg:2,8,2. So it has 2 valence electrons and it will lose these 2 electrons to get into noble state. That's why it becomes Mg^2+.( 12 protons and 10 electrons)

We can explain this in the case of oxygen too. Electronic Configuration of oxygen:2,6. So it has 6 valence electrons. As it is a non metal it will gain electrons. So it will gain 2 electrons to fill its outer shell.So it becomes O^2-( 8 protons + 10 electrons)