Class 11 Chemistry - Chapter Classification of Elements and Periodicity in Properties NCERT Solutions | How would you react to the statement tha

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?

Considering the elements B, C, N, F, and Si, the correct order of their non-metallic character is:
(a) B > C > Si > N > F
b) Si > C > B > N > F
(c) F > N > C > B > Si
d) F > N > C > Si > B

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.

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.

What is meant by hybridisation of atomic orbitals? Describe the shapes of sp, sp^₂, sp³ hybrid orbitals.

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.

Arrange the following

(i) CaH₂, BeH₂ and TiH₂ in order of increasing electrical conductance.

(ii) LiH, NaH and CsH in order of increasing ionic character.

(iii) H-H, D-D and F-F in order of increasing bond dissociation enthalpy.

(iv) NaH, MgH₂ and H₂O in order of increasing reducing property.

Complete the following chemical reactions.

(i) PbS_(s)  +  H₂O_2(aq)   → 

(ii)  MnO^-_4(aq)  +  H₂O_2(aq)   →

(iii)  CaO_(s)  +  H₂O_(g)  →

(iv) AlCl_3(g)   +   H₂O_(I)   →

(v) Ca₃N_2(s)   +  H₂O_(I)  →

Classify the above into (a) hydrolysis, (b) redox and (c) hydration reactions.

What are the oxidation number of the underlined elements in each of the following and how do you rationalise your results ?

(a) KI₃

(b) H₂S₄O₆

(c) Fe₃O₄

(d) CH₃CH₂OH

(e) CH₃COOH

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

Dual behaviour of matter proposed by de Broglie led to the discovery of electron microscope often used for the highly magnified images of biological molecules and other type of material. If the velocity of the electron in this microscope is 1.6 × 10⁶ ms^–1, calculate de Broglie wavelength associated with this electron.

Why is it necessary to use acetic acid and not sulphuric acid for acidification of sodium extract for testing sulphur by lead acetate test?

Why does benzene undergo electrophilic substitution reactions easily and nucleophilic substitutions with difficulty?

Nitrogen laser produces a radiation at a wavelength of 337.1 nm. If the number of photons emitted is 5.6 × 10²⁴, calculate the power of this laser.