Question

Boron has two stable isotopes, ¹⁰B (19%) and ¹¹B (81%). Average
atomic weight for boron in the periodic table is
(a) 10.8 (b) 10.2
(c) 11.2 (d) 10.0

Answer 1

$\bf\large\underline\pink{Answer:-}$

d) 10.0

Answer 2

(a) 10.8

Explanation:

Average Atomic Mass of Boron in the periodic table = (RA1 * MN1 + RA2 * MN2) / (RA1 + RA2) where RA is Relative Abundance, and MN is Mass Number.

= (19 * 10 + 81 * 11) / 100  

= 10.81

Option A is the answer.