If you look on the periodic table, you see that the metals are on the left side. The whole "desire" for elements is to become more like the noble gasses. They want to lose or gain electrons to get to the same number of electrons as the noble gasses. Therefore, if you look at a nonmetal, say oxygen, it wants 2 more electrons to become like neon which has 10 protons and 10 electrons. However, with metals, they want to lose electrons instead of gain them to become like the elements in g18. Na for example wants to have 10 electrons to be like neon. Therefore, with 11 protons, and 10 electrons, it is Na +1 They are called cations-->ions with a positive charge Anions are ions with a negative charge.