Integer Answer Type Questions for JEE: Structure of Atom

Q.1. The ratio of (E₂ - E₁) to (E₄ - E₃) for the hydrogen atom is approximately equal to

Ans. 15

Q.2. Assuming Rydberg's constant (R_H) to be 109670 cm^-1, the longest wavelength line in the Lyman series of the hydrogen spectrum is

Ans. 1215.8 Å

λ = 1215.8 × 10^-8 cm i.e.,
λ = 1215.8 Å

Q.3. The first excitation energy for hydrogen atom would be

Ans. 10.2 eV

Q.4. If electrons are excited to 4th shell in He+ ion, the number of wavelengths emitted by electrons during de-excitation are

Ans. 6
By nc₂formula ie. Total number of transitions = n(n - 1)/2

Q.5. In Mn²⁺ ion, the number of unpaired electrons is

Ans. 5

Q.6. The radius of the first Bohr orbit of hydrogen atom (n = 1) is approximately 0.530 Å. The radius of the first excited state (n = 2) of hydrogen atom is

Ans. 2.12 Å
r_n = r₁ × n² [for hydrogen atom]
r_n = 0.53 × n² Å [n = 2]
= 0.53 × 4
r_n =2.12 Å.

Q.7. An element with atomic number 20 will be placed in the period of the periodic table

Ans. 4
Atomic number 20  → 1s²2s²2p⁶3s²3p⁶4s²

Q.8. How many maximum quantum number can be same for two electrons in an atom.

Ans. 3
Maximum three quantum number can be same but fourth must be different.

Q.9. Find out the number of waves made by a Bohr electron in one complete revolution in its 3rd orbit.

Ans. 3
No of waves = principal quantum no.
n = 3

Q.10. How many unpaired electrons will be in 4f orbital of Gadolinium (64)?

Ans. 8