Question

What happens to the electropositive character of elements on moving from left to right in a periodic table?

• A. Increases
• B. Decreases
• C. First increases than decreases
• D. First decreases than increases

Answer 1

Answer:

B. Decreases

• In Group – Elements have the same number of valence electrons.

  In period – valence shell electrons increase by one unit.

• As the group goes down – the number of shells increases

  In period – moving from left to right, the number of shells remains the same

• Down the group – the atomic radius increases because the effective nuclear charge decreases.

  In the period – the atomic radius decreases because the effective nuclear charge increases by one unit. This brings the valence electrons closer to the nucleus.

• In group – nuclear charge decreases. The tendency to lose valence electrons increases. Hence, the metallic character increases

  In period – As the nuclear charge increases, the tendency to lose valence electrons decreases. Hence, the metallic character is reduced

• In group – nuclear charge decreases. The tendency to gain electrons in the valence shell decreases. Hence, the non-metallic character is reduced

  In period – non-metallic character increases as nuclear charge increases and tendency to gain electrons in valence shell increases.

• In the group – as the nuclear charge decreases, the tendency to gain electrons in the valence shell decreases and the electronegativity decreases.

  In period – As the nuclear charge increases and the tendency to gain electrons in the valence shell increases, the electronegativity increases.