Class 11 Chemistry - Chapter Structure of Atom NCERT Solutions | Lifetimes of the molecules in the excite

The mass of an electron is 9.1 × 10^–31 kg. If its K.E. is 3.0 × 10^–25 J, calculate its wavelength.

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).

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?

Given the standard electrode potentials,

K⁺/K = -2.93V, Ag⁺/Ag = 0.80V,

Hg²⁺/ Hg = 0.79V

Mg²⁺/ Mg = -2.37V. Cr³⁺/ Cr = -0.74V

Arrange these metals in their increasing order of reducing power.

List gases which are responsible for greenhouse effect.

Calculate the mass percent of different elements present in sodium sulphate (Na₂SO₄).

Compare the solubility and thermal stability of the following compounds of the alkali metals with those of the alkaline earth metals.

(a) Nitrates (b) Carbonates (c) Sulphates.

Given

N₂(g) + 3H₂(g) → 2NH₃(g) ; Δ_rH⁰ = –92.4 kJ mol^–1

What is the standard enthalpy of formation of NH₃ gas?

What characteristics do you expect from an electron-deficient hydride with respect to its structure and chemical reactions?

Calculate the degree of ionization of 0.05M acetic acid if its pK_a value is 4.74.

How is the degree of dissociation affected when its solution also contains (a) 0.01 M (b) 0.1 M in HCl?

In the Lassaigne's test for nitrogen in an organic compound, the Prussian blue colour is obtained due to the formation of:

(a) Na4[Fe(CN)6]

(b) Fe4[Fe(CN)6]3

(c) Fe2[Fe(CN)6]

(d) Fe3[Fe(CN)6]4

Comment on the thermodynamic stability of NO(g), given

1/2 N₂(g) + 1/2 O₂(g) → NO(g) ; Δ_rH⁰ = 90 kJ mol^–1

NO(g) + 1/2 O₂(g) → NO₂(g) : Δ_rH⁰= –74 kJ mol^–1

Which element do you think would have been named by
(i) Lawrence Berkeley Laboratory
(ii) Seaborg’s group?