Question

in periodic table if we go left to right in periods the atomic no. increase and atomic size decreases why?
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Answer 1

Answer:

As we move from left to right in a period, the number of protons increases inside the nucleus with the number of shells being constant. Also, the size of the electrons is very small as compared to that of a proton, hence increase in the number of electrons hardly makes any difference.

Therefore, the nuclear charge increases subsequently that pulls the electrons more and more towards it thus making the atomic size smaller.

Answer 2

Explanation:

because of additional repulsions between electrons(inter - electronic repulsion ) atomic side increases

And the decreases because of the additional protons in the nucleus, no effect at all as the two opposing tendencies of electron repulsion and nuclear attraction balance each other out.