Question

The wave number of the first line of Balmer series of H atom is 15200 $C{m}^{-1}$.What is the wave number of the first line of Balmer series of $L{i}^{2+}$ion?

• A. 15200$C{m}^{-1}$
• B. 6080$C{m}^{-1}$
• C. 76000$C{m}^{-1}$
• D. 136800$C{m}^{-1}$

Answer 1

The correct option is D 136800$C{m}^{-1}$

for H atom$=15200C{m}^{-1}$

for$L{i}^{2+}$ atom=$Z^2\times$15200$C{m}^{-1}$

$={\left(3\right)}^2\times 1520$

$=136800C{m}^{-1}$