Two elements M and N beong to group I and II respectively and are in the same period of the periodic tabe. How do the follwoing properties of M and N vary ?
Sizes of their atoms

Explanation

a) The vertical columns in the periodic table are called group. The horizontal rows in the periodic table are called periods. b) 1. M and N belong to the same period but I and II. Therefore N will be smaller than Mas atomic size is decreasing from left to right. 2. M is more metallic than N. Metallic character goes on decreasing from left to right as tendency to lose electrons decreases due to decrease in atomic size. 3. Their valencies are 1 and 2 respectively in forming oxides. Valency goes on increasing first and then increases. 4. `MCI, NCI_2` are molecular formulae of their chlorides.