NCERT solutions for Chemistry - Part 1 and 2 [English] Class 11 chapter 3 - Classification of Elements and Periodicity in Properties [Latest edition]

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

Which important property did Mendeleev use to classify the elements in his periodic table and did he stick to that?

What is the basic difference in approach between the Mendeleev’s Periodic Law and the Modern Periodic Law?

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

In terms of period and group, where would you locate the element with Z =114?

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

Which element do you think would have been named by Lawrence Berkeley Laboratory?

Which element do you think would have been named by Seaborg’s group?

Why do elements in the same group have similar physical and chemical properties?

What does atomic radius and ionic radius really mean to you?

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

What do you understand by isoelectronic species? Name a species that will be isoelectronic with the following atom or ion:-

F^-

What do you understand by isoelectronic species? Name a species that will be isoelectronic with the following atom or ion:-

Ar

What do you understand by isoelectronic species? Name a species that will be isoelectronic with the following atom or ion:-

Mg²⁺

What do you understand by isoelectronic species? Name a species that will be isoelectronic with the following atom or ion:-

Rb⁺

Consider the following species:-

N^3–, O^2–, F^–, Na⁺, Mg²⁺ and Al³⁺

What is common in them?

Consider the following species:-

N^3–, O^2–, F^–, Na⁺, Mg²⁺ and Al³⁺

Arrange them in the order of increasing ionic radii.

Explain why cations are smaller and anions larger in radii than their parent atoms?

What is the significance of the terms - ‘isolated gaseous atom’ and ‘ground state’ while defining the ionization enthalpy and electron gain enthalpy?

Hint: Requirements for comparison purposes.

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.
Hint: Apply the idea of mole concept to derive the answer.

Among the second period elements the actual ionization enthalpies are in the

order Li < B < Be < C < O < N < F < Ne.

Explain why Be has higher Δ_iH than B?

Among the second period elements the actual ionization enthalpies are in the

order Li < B < Be < C < O < N < F < Ne.

Explain why O has lower Δ_iH than N and F?

How would you explain the fact that the first ionization enthalpy of sodium is lower than that of magnesium but its second ionization enthalpy is higher than that of magnesium?

What are the various factors due to which the ionization enthalpy of the main group elements tends to decrease down a group?

The first ionization enthalpy values (in kJmol^–1) of group 13 elements are:-

How would you explain this deviation from the general trend?

Which of the following pair of elements would have a more negative electron gain enthalpy?

O or F

Which of the following pair of elements would have a more negative electron gain enthalpy?

F or Cl

Would you expect the second electron gain enthalpy of O as positive, more negative or less negative than the first? Justify your answer.

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

How would you react to the statement that the electronegativity of N on Pauling scale is 3.0 in all the nitrogen compounds?

Describe the theory associated with the radius of an atom as it gains an electron.

Describe the theory associated with the radius of an atom as it loses an electron.

Would you expect the first ionization enthalpies for two isotopes of the same element to be the same or different? Justify your answer.

What are the major differences between metals and non-metals?

Use the periodic table to answer the following question.

Identify an element with five electrons in the outer subshell.

Use the periodic table to answer the following question.

Identify an element that would tend to lose two electrons.

Use the periodic table to answer the following question.

Identify an element that would tend to gain two electrons.

Use the periodic table to answer the following question.

Identify the group having metal, non-metal, liquid as well as gas at room temperature.

The increasing order of reactivity among group 1 elements is Li < Na < K < Rb <Cs whereas that among group 17 elements is F > CI > Br > I. Explain.

Write the general outer electronic configuration of s- block elements.

Write the general outer electronic configuration of p- block elements.

Write the general outer electronic configuration of d- block elements.

Write the general outer electronic configuration of f- block elements.

Assign the position of the element having an outer electronic configuration in the periodic table.

ns² np⁴ for n = 3

Assign the position of the element having an outer electronic configuration in the periodic table.

(n - 1)d² ns² for n = 4

Assign the position of the element having an outer electronic configuration in the periodic table.

(n - 2) f⁷ (n - 1)d¹ ns² for n = 6

The first (Δ₁H₁) and the second (Δ₁H₂) ionization enthalpies (in kJ mol^-1) and the (Δ_egH) electron gain enthalpy (in kJ mol^-1) of a few elements are given below:

Which of the above elements is likely to be the least reactive element.

The first (Δ₁H₁) and the second (Δ₁H₂) ionization enthalpies (in kJ mol^-1) and the (Δ_egH) electron gain enthalpy (in kJ mol^-1) of a few elements are given below:

Which of the above elements is likely to be the most reactive metal.

The first (Δ₁H₁) and the second (Δ₁H₂) ionization enthalpies (in kJ mol^-1) and the (Δ_egH) electron gain enthalpy (in kJ mol^-1) of a few elements are given below:

Which of the above elements is likely to be the most reactive non-metal.

The first (Δ₁H₁) and the second (Δ₁H₂) ionization enthalpies (in kJ mol^-1) and the (Δ_egH) electron gain enthalpy (in kJ mol^-1) of a few elements are given below:

Which of the above elements is likely to be the least reactive non-metal.

The first (Δ₁H₁) and the second (Δ₁H₂) ionization enthalpies (in kJ mol^-1) and the (Δ_egH) electron gain enthalpy (in kJ mol^-1) of a few elements are given below:

Which of the above elements is likely to be the metal which can form a stable binary halide of the formula MX₂, (X=halogen).

The first (Δ₁H₁) and the second (Δ₁H₂) ionization enthalpies (in kJ mol^-1) and the (Δ_egH) electron gain enthalpy (in kJ mol^-1) of a few elements are given below:

Which of the above elements is likely to bethe metal which can form a predominantly stable covalent halide of the formula MX (X = halogen)? 

Predict the formula of the stable binary compounds that would be formed by the combination of the following pair of elements.

Lithium and oxygen

Predict the formula of the stable binary compounds that would be formed by the combination of the following pair of elements.

Magnesium and nitrogen

Predict the formula of the stable binary compounds that would be formed by the combination of the following pair of elements.

Aluminium and iodine

Predict the formula of the stable binary compounds that would be formed by the combination of the following pair of elements.

Silicon and oxygen

Predict the formula of the stable binary compounds that would be formed by the combination of the following pair of elements.

Phosphorus and fluorine

Predict the formula of the stable binary compounds that would be formed by the combination of the following pair of elements.

Element 71 and fluorine

In the modern periodic table, the period indicates the value of:-

Which of the following statements related to the modern periodic table is incorrect?

Anything that influences the valence electrons will affect the chemistry of the element. Which one of the following factors does not affect the valence shell?

The size of isoelectronic species — F^-, Ne and Na⁺ is affected by ______.

Which one of the following statements is incorrect in relation to ionization enthalpy?

Considering the elements B, Al, Mg, and K, the correct order of their metallic character is ______.

Considering the elements B, C, N, F, and Si, the correct order of their non-metallic character is:

Considering the elements F, Cl, O and N, the correct order of their chemical reactivity in terms of oxidizing property is ______.