1. The energy absorbed by each molecule \[\left(A_{2}\right)\] of a substance is \[4.4×10^{-19}j \] and bond energy per molecule is \[4.0×10^{-19}j \] . The kinetic energy of the molecule per atom will be:

a) \[2.2×10^{-19}J\]

b) \[2.0×10^{-19}J\]

c) \[4.0×10^{-20}J\]

d) \[2.0×10^{-20}J\]

Explanation:

2. Maximum number of electrons in a subshell of an atom is determined by the following

a) \[2\ell+1\]

b) \[4\ell-2\]

c) \[2n^{2}\]

d) \[4\ell+2\]

Explanation: The number of sub shell is (2 l + 1). The maximum number of electrons in the sub shell is 2 (2 l + 1) = (4 l + 2)

3. Which of the following is not permissible arrangement of electrons in an atom?

a) n = 5, l = 3, m = 0, s = + 1/2

b) n = 3, l = 2, m = – 3, s = – 1/2

c) n = 3, l = 2, m = – 2, s = – 1/2

d) n = 4, l = 0, m = 0, s = – 1/2

Explanation: m = – l to +l, through zero thus for l = 2, values of m will be – 2, –1, 0, + 1, + 2

Therefore for l = 2, m cannot have the value –3.

4. A 0.66 kg ball is moving with a speed of 100 m/s. The associated wavelength will be \[\left(h=6.6*10^{-34} Js\right)\] :

a) \[1.0 * 10^{-32}m\]

b) \[6.6 * 10^{-32}m\]

c) \[6.6 * 10^{-34}m\]

d) \[1.0 * 10^{-35}m\]

Explanation:

5. The total number of atomic orbitals in fourth energy level of an atom is :

a) 8

b) 16

c) 32

d) 4

Explanation: Total no. of atomic orbitals in a shell = n

^{2}

Given n = 4; Hence number of atomic orbitals in 4

^{th}shell will be 16.

6. The energies \[E_{1} and E_{2}\] of two radiations are 25 eV and 50 eV, respectively. The relation between their wavelengths i.e., \[\lambda_{1} \] and \[\lambda_{2} \] will be :

a) \[\lambda_{1}=\lambda_{2}\]

b) \[\lambda_{1}=2\lambda_{2}\]

c) \[\lambda_{1}=4\lambda_{2}\]

d) \[\lambda_{1}=\frac{1}{2}\lambda_{2}\]

Explanation:

7. If n = 6, the correct sequence for filling of electrons will be :

a) \[ns\rightarrow\left(n-2\right)f\rightarrow\left(n-1\right)d\rightarrow np\]

b) \[ns\rightarrow\left(n-1\right)f\rightarrow\left(n-2\right)d\rightarrow np\]

c) \[ns\rightarrow\left(n-2\right)f\rightarrow np\rightarrow\left(n-1\right)d \]

d) \[ns\rightarrow np\rightarrow \left(n-1\right)d\rightarrow\left(n-2\right)f\]

Explanation:

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

a) n = 6 to n = 1

b) n = 5 to n = 4

c) n = 6 to n = 5

d) n = 5 to n = 3

Explanation:

9. The value of Planck’s constant is \[6.63 × 10^{-34} Js\] . The speed of light is \[3 × 10^{17}\] nm \[s^{-1}\] Which value is closest to the wavelength in nanometer of a quantum of light with frequency of \[6 × 10^{15} s^{-1}\] ?

a) 25

b) 50

c) 75

d) 10

Explanation:

10. 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

a) 6

b) 4

c) 2

d) 10

Explanation: n = 3 for 3

^{rd}shell

l = 1 for p sub shell

m = – 1 is possible for two electrons present in an orbital.