Question

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.

Answer 1

In the Modern Periodic Table, there are 18 vertical columns known as Groups and 7 horizontal rows known as Periods.

As we move down the group, the electrostatic attraction between the nucleus and the outer-most electron decreases due to increase in the distance between them. This happens because, on moving down the group, a new shell is added. So the valence electron can be easily lost by the element. As we know, metallic character is characterised by the ease of loss of an electron, thereby, metallic character increases on moving down a group in the Modern Periodic Table.

When we move across a period, the number of electrons in the same shell increases. This leads to greater electrostatic attraction between the nucleus and the outer-most electron. This increased attraction pulls the outer-most electron closer to the nucleus, thereby decreasing the atomic size.