Bohr model: energy, radius, velocity, ionisation energy

25 questions on Bohr model: energy, radius, velocity, ionisation energy from the Atomic Structure chapter: 5 NEET level, 11 JEE Main, 9 JEE Advanced. Each one opens with its answer and solution.

• The energy of the electron in the n = 2 level of a hydrogen atom, taking E_1 = -13.6 eV, is NEET level
• The radius of the third Bohr orbit of hydrogen is how many times the radius of the first Bohr orbit? NEET level
• Which relation expresses Bohr's quantisation of the angular momentum of the electron in a hydrogen atom? NEET level
• Take E_1 = -13.6 eV for hydrogen. The ionisation energy of the ground-state He+ ion is NEET level
• The speed of the electron in the second Bohr orbit of hydrogen, compared with its speed in the first orbit, is NEET level
• Take E_1 = -13.6 eV for hydrogen. The energy of an electron in the n=2 level of Li^2+ is JEE Main level
• Use a_0 = 0.529 AA. The radius of the third Bohr orbit of He+ is JEE Main level
• The speed of the electron in the n=2 orbit of B^4+ is how many times the speed of the electron in the first orbit of hydrogen? JEE Main level
• Using E_1 = -13.6 eV, the minimum energy needed to excite a ground-state hydrogen atom to the n=3 level is JEE Main level
• Take E_1=-13.6 eV for hydrogen. In the n=2 level of Be^3+, the potential energy of the electron is JEE Main level
• Use a_0 = 52.9 pm. Calculate the radius of the fourth Bohr orbit of Li^2+ in pm (nearest integer). JEE Main level
• Take the speed of the electron in the first Bohr orbit of hydrogen as 2.19x10^6 m s^-1. Find its speed in the n=3 orbit, in units of 10^5 m s^-1 (two decimals). JEE Main level
• The ionisation energy of a hydrogen atom is 13.6 eV. Using 1 eV = 1.6x10^-19 J and N_A = 6.022x10^23 mol^-1, express it in kJ mol^-1 (nearest integer). JEE Main level
• Use a_0 = 0.529 AA and take the speed in the first Bohr orbit of hydrogen as 2.19x10^6 m s^-1. Calculate the time period of revolution of the electron in the n=... JEE Main level
• Consider the ground states (n=1) of H, He+ and Li^2+ in the Bohr model. Select the correct statements. JEE Main level
• For an electron in successive Bohr orbits of hydrogen, which quantities increase as n increases from 1 to 4? JEE Main level
• The de Broglie wavelength of the electron in the n=4 orbit of Li^2+ is compared with that in the n=1 orbit of H. The ratio is JEE Advanced level
• When a hydrogen-like ion drops from n=2 to n=1 it emits a photon of 91.8 eV. Using E_1 = -13.6 eV for hydrogen, the ionisation energy of this ion in its ground ... JEE Advanced level
• In the Bohr model, the frequency of revolution of the electron in the n=2 orbit of He+ divided by that in the n=1 orbit of H is JEE Advanced level
• The n=2 level of a hydrogen-like ion has energy -30.6 eV (take E_1 = -13.6 eV for hydrogen and a_0 = 0.529 AA). The radius of its third Bohr orbit is JEE Advanced level
• Use a_0 = 0.529 AA and a first-orbit speed of 2.19x10^6 m s^-1 for hydrogen. An electron stays in the n=2 orbit for 1.0x10^-8 s before dropping to a lower level... JEE Advanced level
• Use m_e = 9.1x10^-31 kg, 1 eV=1.6x10^-19 J and E_1=-13.6 eV. A free electron collides with a ground-state hydrogen atom and just excites it to the first excited... JEE Advanced level
• Compare the electron in the n=2 orbit of He+ with that in the n=2 orbit of H. Select the correct statements. JEE Advanced level
• Compare the electron in the n=3 orbit of Li^2+ with that in the n=1 orbit of H. Select the correct statements. JEE Advanced level
• The electron in hydrogen moves from the n=2 orbit to the n=4 orbit. Select the correct statements. JEE Advanced level