Question

The general trend for the first ionization energy (energy necessary to remove an electron from an atom) for Representative elements is as follows:

a. increases across the table and from top to bottom

b. decreases across the table and from the top to bottom

c. increases across the table and decreases fro top to bottom

d. decreases across the table and increases from top to bottom

Answer 1

Ans: (c) increases across the table (in periods) and decreases from top to bottom (in column)

This is because, As we move across a period, there is both an increase in effective nuclear charge and a decrease in atomic radius, causing the ionization energy to increase. However, as we move down a column, the atomic radius increases, while the effective nuclear charge remains essentially constant. Thus, the attraction between the nucleus and the electron decreases in this direction, causing the ionization energy to decrease.