Question

The chemistry states that effective nuclear charge increases as atomic number increases nd atomic size decreases across the period . but in titanium the effective nuclear charge is greater than chromium.. so how does this fit to the statement. give example by explaining the two atoms i.e Titanium and Chromium​

Answer 1

Answer:

With an increase in atomic number, nuclear charge increase both in a period and in a group. In a period, the differentiating electron is added to the same shell at the same distance from the nucleus. The number of inner electrons also remain same and screening effect remains constant. As a result, effective nuclear charge increases. Atomic radius decreases and IP increases.

In a group, differentiating electron is added to a shell which is further from nuclei charge is more than compensated by these factors. Therefore, effective nuclear charge decreases. Atomic radius increases and IP decreases.