An electron revolves round Li nucleus at a distance of 1.587 Å. The speed of electron should be — Atomic Structure Chemistry Question

💡 Solution & Explanation

Radius $r = 0.529 \frac{n^2}{Z}$. Given $Z=3$ and $r = 1.587$ Å. $1.587 = 0.529 \frac{n^2}{3} \implies n^2 = \frac{1.587 \times 3}{0.529} = 9 \implies n = 3$. Speed $v = 2.188 \times 10^6 \frac{Z}{n} = 2.188 \times 10^6 \times \frac{3}{3} = 2.188 \times 10^6$ m/s. Therefore, correct answer is A.