2, 8, 1
2, 8, 2
2, 8, 3
Positive ions in a "sea of electrons"
The attraction of oppositely charged ions
By giving one pair of electrons to the oxygen atom.
By sharing one pair of electrons, both electrons provided by the magnesium atom.
By sharing two pairs of electrons, both pairs provided by the oxygen atom.
By sharing two pairs of electrons, each atom donating one pair of electrons.
Carbon and chlorine
Fluorine and sodium
Hydrogen and oxygen
Oxygen and carbon
Here's an interesting quiz for you.