NEET Structure of Atom — Set 17

Question 1

What is the maximum number of electrons that can occupy the subshell with principal quantum number $ n = 2 $ and azimuthal quantum number $ l = 1 $?

Accepted Answer

For $ l = 1 $ (p subshell), number of orbitals = $ 2l + 1 = 3 $. Each orbital holds 2 electrons, so total = $ 3 \times 2 = 6 $.

Question 2

A photon of wavelength $ 200 \, \text{nm} $ ejects an electron from a metal with a velocity of $ 6.62 \times 10^5 \, \text{m s}^{-1} $. What is the work function of the metal? ($ h = 6.626 \times 10^{-34} \, \text{J s} $, $ c = 3.0 \times 10^8 \, \text{m s}^{-1} $, $ m_e = 9.1 \times 10^{-31} \, \text{kg} $)

Accepted Answer

Photon energy $ E = \frac{hc}{\lambda} = \frac{6.626 \times 10^{-34} \times 3.0 \times 10^8}{200 \times 10^{-9}} = 9.939 \times 10^{-19} \, \text{J} $. $ KE = \frac{1}{2} m v^2 = \frac{1}{2} \times 9.1 \times 10^{-31} \times (6.62 \times 10^5)^2 = 1.994 \times 10^{-19} \, \text{J} $. $ W_0 = E - KE = 9.939 \times 10^{-19} - 1.994 \times 10^{-19} = 7.945 \times 10^{-19} \, \text{J} $.

Question 3

The number of spectral lines produced when an electron in a hydrogen atom falls from $ n = 5 $ to $ n = 2 $ is:

Accepted Answer

Transitions: 5→2, 5→3→2, 5→4→2, 4→2, 3→2. Total = 5 lines.

NEET Chemistry: Structure of Atom — Practice Set 17

Q1. What is the maximum number of electrons that can occupy the subshell with principal quantum number \( n = 2 \) and azimuthal quantum number \( l = 1 \)?

Q3. The number of spectral lines produced when an electron in a hydrogen atom falls from \( n = 5 \) to \( n = 2 \) is:

Q4. What is the wavelength of the second line in the Balmer series of a hydrogen atom? (\( R_H = 1.097 \times 10^7 \, \text{m}^{-1} \))

Q5. The velocity of an electron in the second orbit of a hydrogen atom is \( 1.095 \times 10^6 \, \text{m s}^{-1} \). What is its de Broglie wavelength in this orbit? (\( h = 6.626 \times 10^{-34} \, \text{J s} \), \( m_e = 9.1 \times 10^{-31} \, \text{kg} \))

Q7. A metal has a threshold wavelength of \( 450 \, \text{nm} \). What is the kinetic energy of an electron ejected by light of wavelength \( 300 \, \text{nm} \)? (\( h = 6.626 \times 10^{-34} \, \text{J s} \), \( c = 3.0 \times 10^8 \, \text{m s}^{-1} \))

Q8. The number of electrons in an atom with quantum numbers \( n = 4, l = 1, m_l = 0 \) is:

Q9. An electron in the second orbit of \( \text{He}^+ \) has a velocity of \( 2.19 \times 10^6 \, \text{m s}^{-1} \). What is its de Broglie wavelength? (\( h = 6.626 \times 10^{-34} \, \text{J s} \), \( m_e = 9.1 \times 10^{-31} \, \text{kg} \))

Q10. The threshold frequency for a metal is \( 6.0 \times 10^{14} \, \text{Hz} \). What is the work function in joules? (\( h = 6.626 \times 10^{-34} \, \text{J s} \))