Question

Which of the following properly explains why the atomic radius decreases going cross a period from left to right?

• A. As you cross the period from left to right, the number of electron orbital shells decreases as the number of protons remains constant.
• B. As you cross the period from left to right, the number of protons decreases as the number of electron orbitals remains constant.
• C. As you cross the period from left to right, the number of electron orbital shells increases as the number of protons remains constant.
• D. As you cross the period from left to right, the number of protons increases as the number of electron orbitals remains constant.

Answer 1

The correct option is D As you cross the period from left to right, the number of protons increases as the number of electron orbitals remains constant.

As we move towards right, the electrons are added in same shell hence number of orbit as does not increase however, the number of protons increases thus the attractive force increases and hence size decreases. Thus correct option is D.