Write the names given to the vertical columns and horizontal rows in the Modern Periodic Table. How does the metallic charcter of elements very 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 pupport of your answer in the above two cases.

Explanation

Vertical coloumns are called Groups.
The horizontal rows are called Periods.
`**" "`Metallic character increas on going down in a group.
Reason. Abolity to lose electron increases on moving down the group due to increase in distance betweeen the nucleus and the valence electrons. There is decrease in the attraction between the nucleus and the valence electrons.
`**" "`Atomic radius decreases as we move from left to right in a period.
Reason. The nuclear charge increases on moving from left to right across a period resulting in increase in the attraction between the nucleus and the valence electrons.