Structure of Atom - Result Question 19
####19. The radius of hydrogen atom in the ground state is $0.53 \AA$. The radius of $Li^{2+}$ ion (atomic number $=3$ ) in a similar state is
(a) $0.17 \AA$
(b) $0.265 \AA$
(c) $0.53 \AA$
(d) $1.06 \AA$
[1995]
Show Answer
Solution:
- (a) State of hydrogen atom $(n)=1$
(due to ground state)
Radius of hydrogen atom $(r)=0.53 \AA$. Atomic number of $Li(Z)=3$.
Radius of $Li^{2+}$ ion
$=r \times \frac{n^{2}}{Z}=0.53 \times \frac{(1)^{2}}{3}=0.17 \AA$.
