Write the names given to the vertical columns and horizontal rows in the modern periodic table. How does the metallic character of elements vary on moving down a vertical column? How does the size of atomic radius vary on moving left to right in a horizontal row ? Give reason in support of your answer in the above two cases.
(i) There are 18 vertical columns known as groups and 7 horizontal rows called periods,
(ii) Metallic character increases. On moving down a group a new shell is added and valence
electron can be easily lost by the element. Thus, metallic character increases.
(iii) When we move across a period, the number of electrons in the shell increases, which leads to greater electrostatic attraction between the nucleus and the valence electrons this attraction pulls the valence electron closer to the nucleus and thus, size discreases.