Out of the first 100 elements, number of elements having electrons in 3d-orbitals are :

1.  80

2.  10

3.  100

4.  60

Which are in the ascending order of wavelength?

(1) $H_{\alpha },<mspace\; width="1em"></mspace>H_{\beta },<mspace\; width="1em"></mspace>H_{\gamma }$...lines in Balmer series of hydrogen atom

(2) Lyman limit, balmer limit, paschen limit in the hydrogen spectrum

(3) Blue, violet, yellow, red colours in solar spectrum

(4) None of the above

Photoelectric emission is observed from a surface for frequency $v_1$​ and $v_2$ of the incident radiation ($v_1$​>$v_2$​). If the maximum kinetic energies of the photoelectrons in the two cases are in the ratio 1:k, then the threshold frequency $v_0$​ is given by :

(1) $$$\frac{v_2-v_1}{k-1}$

(2) $$$\frac{k{v}_1-v_2}{k-1}$

(3) $$$\frac{k{v}_2-v_1}{k-1}$

(4) $$$\frac{v_2-v_1}{k}$​​

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

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

The maximum number of electrons in a subshell with l = 3 and n = 4 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⁺

Which one of the following ions is the most stable in aqueous solution?

(1) Cr³⁺                         

(2) V³⁺

(3) Ti3+                         

(4) Mn³⁺

(At no. Ti=22, V=23, Cr=24, Mn=25)

The orientation of an atomic orbital is governed by:

1. Azimuthal quantum number

2. Spin quantum number

3. Magnetic quantum number

4. Principal quantum number