Science (English Medium) इयत्ता ११ - CBSE Question Bank Solutions

The elements in which electrons are progressively filled in 4f-orbital are called ______.

In the modern periodic table, elements are arranged in order of increasing atomic numbers which is related to the electronic configuration. Depending upon the type of orbitals receiving the last electron, the elements in the periodic table have been divided into four blocks, viz, s, p, d and f. The modern periodic table consists of 7 periods and 18 groups. Each period begins with the filling of a new energy shell. In accordance with the Arfbau principle, the seven periods have 2, 8, 8, 18, 18, 32 and 32 elements respectively. The seventh period is still incomplete. To avoid the periodic table being too long, the two series of f-block elements, called lanthanoids and actinoids are placed at the bottom of the main body of the periodic table.

The element with atomic number 57 belongs to ______.

In the modern periodic table, elements are arranged in order of increasing atomic numbers which is related to the electronic configuration. Depending upon the type of orbitals receiving the last electron, the elements in the periodic table have been divided into four blocks, viz, s, p, d and f. The modern periodic table consists of 7 periods and 18 groups. Each period begins with the filling of a new energy shell. In accordance with the Arfbau principle, the seven periods have 2, 8, 8, 18, 18, 32 and 32 elements respectively. The seventh period is still incomplete. To avoid the periodic table being too long, the two series of f-block elements, called lanthanoids and actinoids are placed at the bottom of the main body of the periodic table.

Which of the elements whose atomic numbers are given below, cannot be accommodated in the present set-up of the long form of the periodic table?

In the modern periodic table, elements are arranged in order of increasing atomic numbers which is related to the electronic configuration. Depending upon the type of orbitals receiving the last electron, the elements in the periodic table have been divided into four blocks, viz, s, p, d and f. The modern periodic table consists of 7 periods and 18 groups. Each period begins with the filling of a new energy shell. In accordance with the Arfbau principle, the seven periods have 2, 8, 8, 18, 18, 32 and 32 elements respectively. The seventh period is still incomplete. To avoid the periodic table being too long, the two series of f-block elements, called lanthanoids and actinoids are placed at the bottom of the main body of the periodic table.

The elements with atomic numbers 35, 53 and 85 are all ______.

Electronic configurations of four elements A, B, C and D are given below:

(A) 1s²2s²2p⁶

(B) 1s²2s²2p⁴

(C) 1s²2s²2p⁶3s¹

(D) 1s²2s²2p⁵

Which of the following is the correct order of increasing tendency to gain electron:

Illustrate by taking examples of transition elements and non-transition elements that oxidation states of elements are largely based on electronic configuration.

In both water and dimethyl ether \[\ce{(CH3 - \overset{\bullet\bullet}{\underset{\bullet\bullet}{O}} - CH3)}\], oxygen atom is central atom, and has the same hybridisation, yet they have different bond angles. Which one has greater bond angle? Give reason.

Assertion (A): Though the central atom of both \[\ce{NH3}\] and \[\ce{H2O}\] molecules are sp³ hybridised, yet \[\ce{H -N - H}\] bond angle is greater than that of \[\ce{H - O - H}\].

Reason (R): This is because nitrogen atom has one lone pair and oxygen atom has two lone pairs.

For the reaction \[\ce{H2 (g) + I2 (g) ⇌ 2HI (g)}\], the standard free energy is  ∆G^Θ > 0. The equilibrium constant (K ) would be ______.

On increasing the pressure, in which direction will the gas phase reaction proceed to re-establish equilibrium, is predicted by applying the Le Chatelier’s principle. Consider the reaction.

\[\ce{N2 (g) + 3H2 (g) ⇌ 2NH3 (g)}\]

Which of the following is correct, if the total pressure at which the equilibrium is established, is increased without changing the temperature?

At 500 K, equilibrium constant, \[\ce{K_c}\], for the following reaction is 5.

\[\ce{1/2 H2 (g) + 1/2 I2 (g) ⇌ HI (g)}\]

What would be the equilibrium constant \[\ce{K_c}\] for the reaction

\[\ce{2HI (g) ⇌ H2 (g) + I2 (g)}\]

For the reaction : \[\ce{N2 (g) + 3H2 (g) ⇌ 2NH3 (g)}\]

Equilibrium constant `K_C = ([NH3]^2)/([N_2][H_2]^3)`

Some reactions are written below in Column I and their equilibrium constants in terms of Kc are written in Column II. Match the following reactions with the corresponding equilibrium constant

Match standard free energy of the reaction with the corresponding equilibrium constant.

The more positive the value of E^Θ, the greater is the tendency of the species to get reduced. Using the standard electrode potential of redox couples given below find out which of the following is the strongest oxidising agent.

E^Θ values: \[\ce{Fe^{3+} / Fe^{2+} = + 0.77; I2 (s) / I- = + 0.54}\];

\[\ce{Cu^{2+} / Cu = + 0.34; Ag+ / Ag = + 0.80V}\]

Using the standard electrode potential, find out the pair between which redox reaction is not feasible.

E^Θ values: \[\ce{Fe^{3+} / Fe^{2+} = + 0.77; I2/I- = + 0.54}\];

\[\ce{Cu^{2+} / Cu = + 0.34; Ag+ / Ag = + 0.80 V}\]

Thiosulphate reacts differently with iodine and bromine in the reactions given below:

\[\ce{2S2O^{2-}3 + I2 -> S4O^{2-}6 + 2I-}\]

\[\ce{S2O^{2-}3 + 2Br2 + 5H2O -> 2SO^{2-}4 + 2Br- + 10H+}\]

Which of the following statements justifies the above dual behaviour of thiosulphate?

Identify the correct statement (s) in relation to the following reaction:

\[\ce{Zn + 2HCl -> ZnCl2 + H2}\]

(i) Zinc is acting as an oxidant.

(ii) Chlorine is acting as a reductant.

(iii) Hydrogen ion is acting as an oxidant.

(iv) Zinc is acting as a reductant.

Which of the following electrodes will act as anodes, when connected to Standard Hydrogen Electrode?

(i) \[\ce{Al/Al^{3+}; E^Θ = –1.66}\]

(ii) \[\ce{Fe/Fe^{2+}; E^Θ = – 0.44}\]

(iii) \[\ce{Cu/Cu2+ ; E^Θ = + 0.34}\]

(iv) \[\ce{F2 (g)/2F– (aq); E^Θ = + 2.87}\]

On the basis of standard electrode potential values, suggest which of the following reactions would take place? (Consult the book for E^Θ value).

\[\ce{Cu + Zn^{2+} -> Cu^{2+} + Zn}\]

On the basis of standard electrode potential values, suggest which of the following reactions would take place? (Consult the book for E^Θ value).

\[\ce{Mg + Fe^{2+} -> Mg^{2+} + Fe}\]