(a) 3 shells and 2 valence electrons Reason The period of an element determines the number of shells and the group determines the number of valence electrons.
(d) Atomic radius decreases and nuclear charge increases
Helium has highest ionization potential.
| Group numbers | 1 – IA | 2 – IIA | 13 – IIIA | 14 – IVA | 15 – VA | 16 – VIA | 17 – VIIA | 18 – 0 |
|---|---|---|---|---|---|---|---|---|
| 2nd period | Li | D | O | J | Ne | |||
| 3rd period | A | Mg | E | Si | H | M | ||
| 4th period | R | T | I | Q | u | y |
(i) J is the most electronegative element. (ii) R is the most reactive element of group 1. (iii) M is the element from period 3 with least atomic size. (iv) y is the noble gas of the fourth…
Fluorine has the highest Electron affinity.
Sodium is a metal present in period 3 and group 1 of the periodic table.
The electronic configuration of the given elements is as follows : E = 19 = 2, 8, 8, 1 F = 8 = 2, 6 G = 17 = 2,…
(i) The ionization potential of element increases across a period because the atomic size decreases due to an increase in nuclear charge and electrons in the outermost shell are more…
(d) Argon Reason Electron affinity of argon is zero as Argon is in 3rd period and is an inert gas. Electron affinity of inert gases is zero.
The element having three shells with three electrons in the valence shell is in group 13 [III A] and period 3.