Question

Give reason for :-

1. When we go from left to right in periodic table, the atomic size decreases

2. When we go from top to bottom in group, the atomic size increases​

Answer 1

Answer:

Answer follows below

Explanation:

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Answer 2

Explanation:

Moving Across the Periodic Table

As the atomic number increases along each row of the periodic table, the additional electrons go into the same outermost principal energy level (also known as valence level). This can be predicted to lead to

an increase in atomic size because of additional repulsions between electrons,

a decrease in size 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.

Experiments have shown that the first case is what happens: the increase in nuclear charge overcomes the repulsion between the additional electrons in the valence level. Therefore, the size of atoms decreases as one moves across a period from left to right in the periodic table.