Question : a) What are groups and period in the periodic table? b) Two element 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) Size of their atoms 2) This metallic characters 3) Their valencies informing oxides. 4) Molecular formulae 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 element 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) Size of their atoms 2) This metallic characters 3) Their valencies informing oxides. 4) Molecular formulae 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 group I and Ii. Therefore N will be SMALLER than M as a atomic SIZE is decreases from left to right. 2. M is more metallic than N. Metlallic character goes on decreasing from left to right as TENDENCY to lose electrons. 3.Their VALENCIES are 1 and 2 respectively in forming oxides. Valency goes on increasing first and then decreases. 4. MCI, `NCI_2` are molecules formulae of their chlorides.