Mass of neutron is ........................times the mass of electron-

(A) 1840

(B) 1480

(C) 2000

(D) None

Which of the following species has more number of electrons in comparison with the neutrons?

1. Al³⁺

2. O^2-

3. F^-

4. C

The ratio of the difference in energy between the first and second Bohr orbit to that between the second and the third Bohr orbit of hydrogen is -

1. 1/2

2. 1/3

3. 4/9

4. 27/5

The radius of second stationary orbit in Bohr's atom is R. The radius of 3^rd orbit will be:-

1. 9R

2. R/4

3. 9R/4

4. 2R

Bohr's model fails to describe which of the following atoms accurately?
(a) H-atom
(b) D-atom
(c) T-atom
(d) He-atom
(e) Li- atom
Choose the correct option:
1. (a), (b)
2. (b), (c)
3. (a), (b), (c)
4. (d), (e)

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

1.  d_z²,d_xz

2.  d_xz,d_yz

3.  d_z²,d_x²-y²

4.  d_xy,d_x²-y²

Which is the correct order of increasing energy of the listed orbitals in the atom of titanium?

(1) 3s 4s 3p 3d                   

(2) 4s 3s 3p 3d

(3) 3s 3p 3d 4s                   

(4) 3s 3p 4s 3d

What is the maximum numbers of electrons that can be associated with the following set of quantum numbers?

n=3, l = 1 and m=-1

(1) 10
(2) 6
(3) 4
(4) 2

Maximum number of electrons in a subshell 4f is

(1) 14
(2) 16
(3) 10
(4) 12

Which one of the following ions has electronic configuration [Ar]3d⁶?

(At. no: Mn = 25, Fe = 26, Co = 27, Ni =28)

(1) Ni³⁺               

(2) Mn³⁺

(3) Fe³⁺               

(4) Co³⁺