Question 1
What is the basic theme of organisation in the periodic table?

Question 2
Which important property did Mendeleev use to classify the elements in his periodic table and did he stick to that?

Question 3
What is the basic difference in approach between the Mendeleev’s Periodic Law and the Modern Periodic Law?

Question 5
In terms of period and group where would you locate the element with Z =114?

Question 7
Which element do you think would have been named by
(i) Lawrence Berkeley Laboratory
(ii) Seaborg’s group?

Question 8
Why do elements in the same group have similar physical and chemical properties?

Question 9
What does atomic radius and ionic  radius really mean to you?

Question 10
How does atomic radius vary in a period and in a group? How do you explain the variation?

Question 11
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⁺

Question 12
Consider the following species:
N^3–, O^2–, F^–, Na⁺, Mg²⁺ and Al³⁺
(a) What is common in them?
(b) Arrange them in the order of increasing ionic radii.

Question 13
Explain why cations are smaller and anions larger in radii than their parent atoms?

Question 14
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.

Question 16
Among the second period elements the actual ionization enthalpies are in the order
Li < B < Be < C < O < N < F < Ne.
Explain why
(i) Be has higher ΔiH than B
(ii) O has lower ΔiH than N and F?

Question 17
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?

Question 18
What are the various factors due to which the ionization enthalpy of the main group elements tends to decrease down a group?

Question 19
The first ionization enthalpy values (in kJmol–1) of group 13 elements are :
B Al Ga In Tl
801 577 579 558 589
How would you explain this deviation from the general trend?

Question 20
Which of the following pairs of elements would have a more negative electron gain enthalpy?
(i) O or F
(ii) F or Cl

Question 21
Would you expect the second electron gain enthalpy of O as positive, more negative or less negative than the first? Justify your answer.

Question 22
What is the basic difference between the terms electron gain enthalpy and electronegativity?

Question 23
How would you react to the statement that the electronegativity of N on Pauling scale is 3.0 in all the nitrogen compounds?

Question 24
Describe the theory associated with the radius of an atom as it
(a) gains an electron
(b) loses an electron

Question 25
Would you expect the first ionization enthalpies for two isotopes of the same element to be the same or different? Justify your answer.

Question 26
What are the major differences between metals and non-metals?

Question 31
The first (ΔiH1) and the second (ΔiH) ionization enthalpies (in kJ mol–1) and the (ΔegH) electron gain enthalpy (in kJ mol–1) of a few elements are given below:

Question 34
Which of the following statements related to the modern periodic table is incorrect?
(a) The p-block has 6 columns, because a maximum of 6 electrons can occupy all the orbitals in a p-shell.
(b) The d-block has 8 columns, because a maximum of 8 electrons can occupy all the orbitals in a d-subshell.
(c) Each block contains a number of columns equal to the number of electrons that can occupy that subshell.
(d) The block indicates value of azimuthal quantum number (l ) for the last subshell that received electrons in building up the electronic configuration.

Question 35
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?
(a) Valence principal quantum number (n)
(b) Nuclear charge (Z)
(c) Nuclear mass
(d) Number of core electrons.

Question 37
Which one of the following statements is incorrect in relation to ionization enthalpy?
(a) Ionization enthalpy increases for each successive electron.
(b) The greatest increase in ionization enthalpy is experienced on removal of electron from core noble gas configuration.
(c) End of valence electrons is marked by a big jump in ionization enthalpy.
(d) Removal of electron from orbitals bearing lower n value is easier than from orbital having higher n value.

Question 38
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

Question 39
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

Question 40
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