<span>We started with twenty ions of Mg and twenty ions of F. Producing 20 units of AgCl requires twenty MgCl2 since it is the only source of magnesium. Similarly it requires twenty AgF since it is the only source of silver.</span>
Elements are arranged according to their atomic number in increasing order.
When we move left to right we move along a period.The period in the periodic table tell us about the principal quantum number,(n).
When move from top to bottom we are moving in group. The group in the periodic tabletell us about the number of the valence electrons present in the valence shell of the elements of the particular group.
