Class 11th

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans:  option (i) & (iv)

In a multielectron atomic system the energy of an electron depends not only on its principal quantum number (shell), but also on its azimuthal quantum number (subshell). Electrons having the same shells and same subshells have the same energy and they are known as degenerate orbitals.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Option (C)

No. of mole given = $\frac{\mathrm{g}\mathrm{i}\mathrm{v}\mathrm{e}\mathrm{n}\mathrm{}\mathrm{m}\mathrm{a}\mathrm{s}\mathrm{s}\mathrm{}}{\mathrm{m}\mathrm{o}\mathrm{l}\mathrm{a}\mathrm{r}\mathrm{}\mathrm{m}\mathrm{a}\mathrm{s}\mathrm{s}}$

On substituting the value in the above equation, the cal, can be calculated as

no, of mole =  $\frac{5.85\mathrm{}\mathrm{g}\mathrm{}}{58.5\mathrm{}\mathrm{g}\mathrm{}{\mathrm{m}\mathrm{o}\mathrm{l}}^{-1}}$  = 0.1 g

The molarity (M) is given by the formula:

M = $\frac{\mathrm{n}}{{\mathrm{V}}_1}$

On substituting the values in the above equation:

Molarity = $\frac{0.1\mathrm{}\mathrm{m}\mathrm{o}\mathrm{l}\mathrm{}1000\mathrm{}\mathrm{L}}{500}$

= 0.2 mol L^-1

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: option  (iii) & (iv)

The isotopes are defined as atoms with identical atomic numbers but different mass numbers are known as isotopes.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans:  option (ii) Alpha particle (He²⁺)

As the wavelength is inversely proportional to the mass of the particles thus the alpha particles would possess the shortest wavelength among the above given option

$\mathit{\lambda }=\frac{\mathit{h}}{\mathit{m}\mathit{v}}$

This is a Multiple Choice Questions as classified in NCERT Exemplar

Option (iii)

For the conversion from Fahrenheit to Celsius

$\mathrm{F}=\frac{9}{5}\mathrm{C}+32$

 On substituting the values in the above equation,

 200 = $\frac{9}{5}C+32$

         =93.3 $°$  C

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: option (iv) The two electrons present in the 2s orbital have spin quantum numbers MS but of opposite sign.

According to Pauli's Exclusion Principle no two electrons should possess the same set of four quantum numbers. Thus the two electrons present in the 2s orbital have spin quantum numbers MS but of opposite sign.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Option (ii)

Average of readings of student A,

Average of student A = $\frac{3.01+2.99}{2}=3.00$

Average of readings of student B,

Average of student B = $\frac{3.05+2.95}{2}=3.00$

The correct reading is 3. For both A and B, the average value is close to the correct value. Thus, readings of both are accurate.

The readings of student A are also very close to each other and close to the average value. Thus, readings are precise. Also, the readings of student B are also very close to each other and close to the average value.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans: option  (ii)

Fe³⁺, Mn²⁺ Fe³⁺ electronic configuration is 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁵ 4s² Mn²⁺electronic configuration is 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁵ 4s

This is a Multiple Choice Questions as classified in NCERT Exemplar

Ans:  Option (iii) 1:3

The chlorine is a mixture of two isotopes with atomic masses 37U and 35U and its atomic mass is 35.5U. The atomic mass depicts that % composition of Cl-35 is much higher than that of Cl-37 and they are present in the ratio 1:3