Question

Energy required to excite an electron from second to third Bohr orbit of a Hydrogen like atom is 47.2 eV, then

• A. Z = 6
• B. Z = 5
• C. Wavelength of radiation required to excite an electron from ground state to infinity is 36.4 $\stackrel{o}{A}$
• D. Radius of 1st Bohr orbit is 10.6 pm

Answer 1

Answer: (B), (C), (D)

The correct options are
B Z = 5
C Wavelength of radiation required to excite an electron from ground state to infinity is 36.4 $\stackrel{o}{A}$
D Radius of 1st Bohr orbit is 10.6 pm

$△E=13.6Z^2[\frac{1}{m^2}-\frac{1}{n^2}]$
$47.2=13.6Z^2[\frac{1}{4}-\frac{1}{9}]\Rightarrow Z=5$
$r=53\times \frac{n^2}{Z}pm=\frac{53}{5}pm=10.6pm$
Energy required to excite an electron from ground state to infinity is $\frac{1}{\lambda }=1.1\times {10}^7\times Z^2[\frac{1}{1^2}-\frac{1}{{\infty }^2}]\Rightarrow \lambda =36.4\stackrel{o}{A}$