MCQs on Periodic Classification of Elements
1. Find the successive elements of the periodic table with ionisation energies, 2372, 520 and 890 kJ per mol respectively
(a) Li, Be, B
(b) H, He, Li
(c) B, C, N
(d) He, Li, Be
Answer:::: (d)
2. In the modern periodic table, the number of period of the element is the same as
(a) principal quantum number
(b) atomic number
(c) azimuthal quantum number
(d) atomic mass
Answer:::: (a)
3. The correct order for the size of I, I+, I– is
(a) I > I– > I+
(b) I > I+ > I–
(c) I– > I > I+
(d) I+ > I– > I
Answer:::: (c)
4. For the same value of n, the penetration power of orbital follows the order
(a) s = p = d = f
(b) p > s > d > f
(c) f < d < p < s
(d) s < p < d < f
Answer:::: (c)
5. Which of the reactions will need the maximum amount of energy?
(a) Na → Na+ + e–
(b) Ca+ → Ca++ + e–
(c) K+ → K+ ++ e–
(d) C2+ → C3+ + e–
Answer:::: (c)
6. Which of the following statements is incorrect?
(a) I.E.1 of O is lower than that of N but I.E.2 O is higher than that of N
(b) The enthalpy of N to gain an electron is almost zero but of P is 74.3 kJ mol-1
(c) isoelectronic ions belong to the same period
(d) The covalent radius of iodine is less than its Van der Waal’s radius
Answer:::: (c)
7. The correct order of electronegativity is
(a) Cl > F > O > Br
(b) F > O > Cl > Br
(c) F > Cl > Br > O
(d) O > F > Cl > Br
Answer:::: (b)
8. Two different beakers contain M1-O-H, and M2-O-H solutions separately. Find the nature of the two solutions if the electronegativity of M1 = 3.4, M2 = 1.2, O = 3.5, H = 2.1
(a) acidic, acidic
(b) basic, acidic
(c) basic, basic
(d) acidic, basic
Answer:::: (d)
9. Which one is the most acidic among these?
(a) MgO
(b) CaO
(c) Al2O3
(d) Na2O
Answer:::: (c)
10. Which one will have the highest 2nd ionisation energy?
(a) 1s2 2s2 2p6 3s1
(b) 1s2 2s2 2p4
(c) 1s2 2s2 2p6
(d) 1s2 2s2 2p6 3s2
Answer:::: (a)
