Question

2. What is atomic radius? What does atomic radius decreases across a period?
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Answer 1

Answer:

Atomic radius is the number of shells present in the atoms , the larger the number of shells, the larger the atomic radius.

Explanation:

The atomic radius decreases across a period because the number of shells present in the elements keeps decreasing.

Answer 2

Answer:

Distance from the center of the nucleus to the valence shell of electrons.

Explanation:

Atomic radius decreases across a period due to increase in effective nuclear charge which pulls the valence shell of electrons more closer to the center.

As we go across the period, the metallic character decreases. As a result, elements are more prone to gain electrons which also adds protons to the nucleus. This increases the charge of the nucleus and therefore the nucleus pulls the valence shell (outermost shell of the atom) closer, hence decreasing the atomic radius.

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