Chapter 2: Quantum Mechanical Model of Atom

Electronic configuration of species M²⁺ is 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁶ and its atomic weight is 56. The number of neutrons in the nucleus of species M is

(c) 30

The energy of light of wavelength 45nm is

(c) 4.42 × 10^-18 J

The energies E₁ and E₂ of two radiation are 25 eV and 50 eV respectively. The radiation between their wavelengths ie., λ₁ and λ₂ will be

(b) λ₁ = 2 λ₂

Splitting of spectral lines in an electric field is called

(d) stark effect

Based on equation E = -2.178 × 10^-18 J(z²/n²), certain conclusions are written. Which of them is not correct?

(b) For n – 1 , the electron has a more negative energy then it does for n = 6 which means that the eiectron is more loosely bound in the smallest allowed orbit

According to the Bohr Theory , which of the following transitions in the hydrogen atom will give rise to least energetic photon?

(d) n = 6 to n = 5

Assertion:The spectrum of He⁺ is expected to be similar to that of hydrogen
Reason: He⁺ is also one electron system.

(a) If both assertion and reason are true and reason is the correct explanation of assertion.

Which of the following pairs of d-orbitals will have electron density along the axes?

(c) dx², dx² – y²

Two electron occupying the same orbital are distinguished by

(b) Spin quantum number

The electronic configuration of Eu (Atomic no, 63), Gd (Atomic no . 64), and Tb (Atomic no. 65) are

(b) [Xe] 4f⁷ 6s², [Xe] 4f¹ 5d¹ 6s² and [Xe] 4f⁹ 6s²

The maximum number of electrons in a sub shell is given by the expression

(c) 4l + 2

For d-electrons, the orbit angular momentum is

(d) 6√ h/2π

What is the maximum number electrons that car be associated with following set of quantum numbers? n = 3, l = 1 and m = -1

(c) 2

Assertion:The number of radials and angular nodes for 3p orbital are I, 1 respectively.
Reason:The number of radials and angular nodes depends only one the quantum number.

(c) Assertion is true but the reason is false

The total number of orbitals associated with the principal quantum number n = 3 is

(a) 9

If n = 6, the sequence for filling electrons will be,

(a) ns → (n – 2)f → (n – 1)d → np

Consider the following sets of quantum numbers:

Which of the following sets of quantum numbers is not possible?

(b) (ii), (iv) and (v)

How many electrons in an atom with atomic number 105 can have (n + l) = 8?

(b) 17

Electron density in the yz plane of 3d_{x² – y²} orbital is

(a) zero

If uncertainty in position and momentum are equal, then minimum uncertainty in velocity is

(c) 1/2m√hπ

A macroscopic particle of mass 100 g and moving at a velocity of 100 cm s^-1 will have a de Broglie wavelength of

(c) 6.6 × 10^-31 cm

The ratio of de Broglie wavelengths of a deuterium atom to that of an α – particle, when the velocity of the former is five times greater than that of later, is

(d) 0.4

The energy of an electron in the 3rd orbit of a hydrogen atom is -E. The energy of an electron in the first orbit will be

(d) -9E

Time independent Schnodinger wave equation is

(a) Hψ = Eψ

Which of the following does not represent the mathematical expression for the Heisenberg uncertainty principle?

(d) ∆E . ∆x ≥ h4π