Question

The radius of hydrogen atom is $0.53\mathring{A}$ . The radius of ${}_{3}L{i}^{2+}$ is of:

• A. $1.27\mathring{A}$
• B. $0.17\mathring{A}$
• C. $0.57\mathring{A}$
• D. $0.99\mathring{A}$

Answer 1

Answer: (B)

The radius of hydrogen atom $=0.53\mathring{A}$
${}_{3}L{i}^{+2}$ ion also has only one electron but it has 3 protons in nucleus, hence its electron fells three times more attraction from nucleus in comparison of hydrogen atom. Thus, the radius of ${}_{3}L{i}^{+2}$ will be
$=\frac{0.53}{3}=0.17\mathring{A}$