If the principal quantum number n=6, the correct sequence of filling of electrons will be:

(1) ns→np→(n-1)d→(n-2)f

(2) ns→(n-2)f→(n-1)d→np

(3) ns→(n-1)d→(n-2)f→np

(4) ns→(n-2)f→np→(n-1)d

 

 

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 elements with the following outer orbital configurations may exhibit the

largest number of oxidation states ?

1. 3d³, 4s²

2. 3d⁵, 4s¹

3. 3d⁵, 4s²

4. 3d², 4s²

Maximum number of electrons in a subshell of an atom can be determined by which of the following formula :

1. 4l + 2

2. 2l + 1

3. 4l - 2

4. 2n²

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

1. n = 4, l = 0, m = 0, s = –1/2

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

3. n = 3, l = 2, m = –3, s = –1/2

4. n = 3, l = 2, m = –2, s = –1/2

If uncertainty in position and momentum are both equal, then uncertainty in velocity will be: 

1. $\frac{1}{2\mathrm{m}}\sqrt{\frac{\mathrm{h}}{\mathrm{\pi }}}$

2. $\sqrt{\frac{\mathrm{h}}{2\mathrm{\pi }}}$

3. $\frac{1}{\mathrm{m}}\sqrt{\frac{\mathrm{h}}{\mathrm{\pi }}}$

4. $\frac{\mathrm{h}}{\mathrm{\pi }}$

The measurement of the electron position is associated with an uncertainty in momentum which is equal to 1x10^-18 g cm s^-1. The uncertainty in velocity of the electron will be:

(mass of an electron is 9 x 10^-28 g)

1. 1 x 10⁹ cm s^-1                     

2. 1 x 10⁶ cm s^-1

3. 1 x 10⁵ cm s^-1                     

4. 1 x 10¹¹ cm s^-1

Consider the following sets of quantum numbers:

              n         l         m         s

(i)         3         0         0          +1/2

(ii)        2         2         1          +1/2

(iii)       4         3        -2           -1/2

(iv)       1         0        -1           -1/2

(v)        3         2         3           +1/2

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

1. ii, iii and iv                             

2. i, ii, iii and iv

3. ii, iv and v                               

4. i and iii

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)