Solutions of NCERT Class XI Chemistry Chapter 3 CLASSIFICATION OF ELEMENTS AND PERIODICITY IN PROPERTIES

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 seventeenth group of the periodic table.

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

Consider the following species : N3- , O2-, F- , Na+ , Mg2+ and Al3+ (a) What is common in them? (b) Arrange them in the order of increasing ionic r . . .

Explain why cation 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 electr . . .

Among the second period elements the actual ionization enthalpies are in the order Li < B < Be < C < O < N < F < Ne. Explain wh . . .

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 hi . . .

The first ionization enthalpy values (in kJ mol-1) of group 13 elements are : B Al Ga In Tl 801 577 579 558 589 How would you explain this deviation . . .

Which of the following pairs of elements would have a more negative electron gain enthalpy? (i) O or F (ii) 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 (a) gains an electron (b) 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 questions. (a) Identify an element with five electrons in the outer subshell. (b) Identify an element . . .

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

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

Assign the position of the element having outer electronic configuration (i) ns2np4 for n=3 (ii) (n-1)d 2ns2 for n=4, and (iii) (n-2) f 7 (n-1)d 1ns . . .

The first (∆iH1) and the second (∆iH2) ionization enthalpies (in kJ mol-1) and the (∆egH) electron gain enthalpy (in kJ mol-1) of a few elements are . . .

Predict the formulas of the stable binary compounds that would be formed by the combination of the following pairs of elements. (a) Lithium and oxyg . . .

Which one of the following statements is incorrect in relation to ionization enthalpy? (a) Ionization enthalpy increases for each successive electro . . .

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: (a) F > Cl > O > . . .

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