Question

decreases
o af Across period, atomic size
due to
(a) Sheilding effect (b) Photo electric effect
(c) decrease in nuclear force
(d) Increase in nuclear force
​

Answer 1

Answer:

decreases of Across period, atomic size

due to Increase in nuclear force

Answer 2

Answer:

Electrons in an atom can shield each other from the pull of the nucleus. This effect, called the shielding effect, describes the decrease in attraction between an electron and the nucleus in an atom with more than one electron shell.

More the electron shells, greater is the shielding effect experienced by the outermost electrons. Hence screening or shielding effect increases in a group as shells increases from top to bottom but in a period it decreases from left to right because of increase in atomic number and no change in shells. Hence in a period, it does not increase whereas in a group increases.