Class 11 Chemistry - Chapter Classification of Elements and Periodicity in Properties NCERT Solutions | Considering the elements B, C, N, F, and

Write the general outer electronic configuration of s-, p-, d- and f- block elements.

Considering the elements B, Al, Mg, and K, the correct order of their metallic character is:
(a) B > Al > Mg > K
(b) Al > Mg > B > K
(c) Mg > Al > K > B
(d) K > Mg > Al > B

What do you understand by isoelectronic species? Name a species that will be isoelectronic with each of the following atoms or ions.

(i) F^–

(ii) Ar

(iii) Mg²⁺

(iv) Rb⁺

What is the basic difference between the terms electron gain enthalpy and electronegativity?

Assign the position of the element having outer electronic configuration

(i) ns² np⁴ for n = 3 (ii) (n - 1)d² ns² for n = 4, and (iii) (n - 2) f⁷ (n - 1)d¹ ns² for n = 6, in the periodic table.

How does atomic radius vary in a period and in a group? How do you explain the variation?

Use the periodic table to answer the following questions.
(a) Identify an element with five electrons in the outer subshell.
(b) Identify an element that would tend to lose two electrons.
(c) Identify an element that would tend to gain two electrons.
(d) Identify the group having metal, non-metal, liquid as well as gas at the room temperature.

Considering the elements F, Cl, O and N, the correct order of their chemical reactivity in terms of oxidizing property is:
(a) F > Cl > O > N
(b) F > O > Cl > N
(c) Cl > F > O > N
(d) O > F > N > Cl

On the basis of quantum numbers, justify that the sixth period of the periodic table should have 32 elements.

Write the atomic number of the element present in the third period and seventeenth group of the periodic table.

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

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?

Justify the position of hydrogen in the periodic table on the basis of its electronic configuration.

How would you explain the following observations?

(i) BeO is almost insoluble but BeSO₄ in soluble in water,

(ii) BaO is soluble but BaSO₄ is insoluble in water,

(iii) LiI is more soluble than KI in ethanol.

What is K_c for the following equilibrium when the equilibrium concentration of each substance is: [SO₂]= 0.60 M,  [O₂] = 0.82 M  and  [SO₃] = 1.90 M ?

2SO_2(g) + O_2(g)   ↔   2SO_3(g)

What do you understand by the terms:

(i) hydrogen economy

(ii) hydrogenation

(iii) 'syngas'

(iv) water-gas shift reaction

(v) fuel-cell ?

For the reaction at 298 K,

2A + B → C

ΔH = 400 kJ mol^-1and ΔS = 0.2 kJ K^-1mol^-1

At what temperature will the reaction become spontaneous considering ΔH and ΔS to be constant over the temperature range?

Justify that the following reactions are redox reactions:

(a) CuO_(s) + H_2(g) → Cu_(s) + H₂O_(g)

(b) Fe₂O_3(s) + 3CO_(g) → 2Fe_(s) + 3CO_2(g)

(c) 4BCl_3(g) + 3LiAlH_4(s) → 2B₂H_6(g) + 3LiCl_(s) + 3 AlCl_{3 (s)}

(d) 2K_(s) + F_2(g) → 2K⁺F^– _(s)

(e) 4 NH_3(g) + 5 O_2(g) → 4NO_(g) + 6H₂O_(g)

What sorts of informations can you draw from the following reaction ?

(CN)_2(g)  +  2OH^-_(aq)  →  CN^-_(aq) + CNO^-_(aq) + H₂O_(l)

For an isolated system, ΔU = 0, what will be ΔS?

What are the necessary conditions for any system to be aromatic?

How many neutrons and protons are there in the following nuclei?

Calculate the oxidation number of sulphur, chromium and nitrogen in H₂SO₅, Cr₂O^2- ₇ and NO^– ₃. Suggest structure of these compounds. Count for the fallacy.