Question

How does atomic size vary in a period ongoing from left to right

Answer 1

The atomic size decreases.
Going from left to right the electrons are added in the last shell resulting in increase of energy.. thus the electrons tend to stay closer by attraction hence the radius of the atom decrease



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Answer 2

Hi,
The atomic radius decrease from left to right because across the period the effective nuclear charge increases. Across the period the electrons also increase, which increases the protons(as electrons are equal to protons).... So the charge increases and this pulls the valence shell towards the nucleus..... So thus decreasing the size of the atom.
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