Class 11 Chemistry - Chapter Structure of Atom NCERT Solutions | The mass of an electron is 9.1 × 1

Calculate the wavelength of an electron moving with a velocity of 2.05 × 10⁷ ms^–1.

Using s, p, d notations, describe the orbital with the following quantum numbers.

(a) n = 1, l = 0;

(b) n = 3; l =1

(c) n = 4; l = 2;

(d) n = 4; l =3.

Which of the following are isoelectronic species i.e., those having the same number of electrons?

Na⁺, K⁺, Mg²⁺, Ca²⁺, S^2–, Ar

Calculate the wavelength, frequency and wave number of a light wave whose period is 2.0 × 10^–10 s.

How many electrons in an atom may have the following quantum numbers?

(a) n = 4,

(b) n = 3, l = 0

Yellow light emitted from a sodium lamp has a wavelength (λ) of 580 nm. Calculate the frequency (ν) and wave number () of the yellow light.

Indicate the number of unpaired electrons in: (a) P, (b) Si, (c) Cr, (d) Fe and (e) Kr.

Calculate the wave number for the longest wavelength transition in the Balmer series of atomic hydrogen.

A photon of wavelength 4 × 10^–7 m strikes on metal surface, the work function of the metal being 2.13 eV. Calculate

(i) the energy of the photon (eV),

(ii) the kinetic energy of the emission, and

(iii) the velocity of the photoelectron (1 eV= 1.6020 × 10^–19 J).

Find energy of each of the photons which

(i) correspond to light of frequency 3× 1015 Hz.

(ii) have wavelength of 0.50 Å.

How do you account for the formation of ethane during chlorination of methane?

What are hybridisation states of each carbon atom in the following compounds ?

(i) CH₂=C=O,

(ii) CH₃CH=CH₂,

(iii) (CH₃)₂CO,

(iv) CH₂=CHCN,

(v) C₆H₆

What will be the minimum pressure required to compress 500 dm³ of air at 1 bar to 200 dm³ at 30°C?

What are the common physical and chemical features of alkali metals?

Calculate the molecular mass of the following:
(i) H₂O
(ii) CO₂
(iii) CH₄

Assign oxidation number to the underlined elements in each of the following species:

(a) NaH₂PO₄

(b) NaHSO₄

(c) H₄P₂O₇

(d) K₂MnO₄

(e) CaO₂

(f) NaBH₄

(g) H₂S₂O₇

(h) KAl(SO₄)₂.12 H₂O

What is the basic theme of organisation in the periodic table?

Explain the formation of a chemical bond.

Choose the correct answer. A thermodynamic state function is a quantity
(i) used to determine heat changes
(ii) whose value is independent of path
(iii) used to determine pressure volume work
(iv) whose value depends on temperature only.

A liquid is in equilibrium with its vapour in a sealed container at a fixed temperature. The volume of the container is suddenly increased.
a) What is the initial effect of the change on vapour pressure?
b) How do rates of evaporation and condensation change initially?
c) What happens when equilibrium is restored finally and what will be the final vapour pressure?

Calculate the amount of carbon dioxide that could be produced when

(i) 1 mole of carbon is burnt in air.

(ii) 1 mole of carbon is burnt in 16 g of dioxygen.

(iii) 2 moles of carbon are burnt in 16 g of dioxygen.

Write down the products of ozonolysis of 1,2-dimethylbenzene (o-xylene). How does the result support Kekule structure for benzene?

Explain the following reactions

(a) Silicon is heated with methyl chloride at high temperature in the presence of copper;

(b) Silicon dioxide is treated with hydrogen fluoride;

(c) CO is heated with ZnO;

(d) Hydrated alumina is treated with aqueous NaOH solution

Comment on each of the following observations:

(a) The mobilities of the alkali metal ions in aqueous solution are Li⁺ <  Na⁺ <  K⁺ <  Rb⁺ < Cs⁺

(b) Lithium is the only alkali metal to form a nitride directly.

(c) E° for M²⁺(aq) (where M = Ca, Sr or Ba) is nearly constant.

Explain why is sodium less reactive than potassium?

Energy of an electron in the ground state of the hydrogen atom is –2.18 × 10^–18 J. Calculate the ionization enthalpy of atomic hydrogen in terms of J mol^–1.

Define octet rule. Write its significance and limitations.

Why does hydrogen occur in a diatomic form rather than in a monoatomic form under normal conditions?

Differentiate between the principle of estimation of nitrogen in an organic compound by

(i) Dumas method and

(ii) Kjeldahl's method.

Which of the following pairs of elements would have a more negative electron gain enthalpy?
(i) O or F
(ii) F or Cl