Question

how atómic sizes very along period in the long form of periodic table​

Answer 1

• Atomic size DECREASES across a Period from left to right as we face the Table, but INCREASES down a Group, a column of the Periodic Table.
• And thus across the Period nuclear charge predominates, and draws the valence electrons towards the nuclear core, with the result of a marked decrease in atomic radius.

Answer 2

Answer:

Atomic sizes decrease across a period.

Explanation:

Size of atoms decrease with increase in Protons in the nuclei.