Question : a) What are groups and period in the periodic table? b) Two elements M and N belong to group I and II respectively and are in the same period of the periodic table. How do the following properties of M and N vary?1) Sizes of their atoms 2) Their metallic characters. 3) Their valencies informing oxides. 4) Molecular formula of their chlorides.

Question : a) What are groups and period in the periodic table? b) Two

1.	Question : a) What are groups and period in the periodic table? b) Two elements M and N belong to group I and II respectively and are in the same period of the periodic table. How do the following properties of M and N vary?1) Sizes of their atoms 2) Their metallic characters. 3) Their valencies informing oxides. 4) Molecular formula of their chlorides.
Answer» Solution : 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.