Question

define atomic size, give its unit of measure in the modern periodic table what trend is observed in atomic radius in a group and periodic and why is it so​

Answer 1

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Answer 2

Answer:

Atomic size:

The distance from the center of the nucleus of an isolated atom to the outermost shell containing electrons is known as atomic size. The unit of measurement is Angstroms (

A

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)

Variation in Group:

In a group, the atomic radius increases downwards. In a group, as we move from one element to the other, there is always an increase in the number of electrons shells by one so size increases.

Variation in the period:

In a period, as we go from left to right, the atomic radius decreases because of an increase in the effective nuclear charge. (since electrons gradually added in the same shell)

Explanation:

In the modern periodic table, the atomic size of elements increases down the group and the atomic size decrease along the period from left to right. Down the group, as the number of energy shells of the atoms keeps on increasing from top to bottom so, the atomic radius also increases.