50 MCQ Questions on Periodic Properties
1. Modern Periodic Law states that the physical and chemical properties of elements are a periodic function of their:
A) Atomic mass
B) Atomic number
C) Valency
D) Density
2. Periodicity is mainly caused by:
A) Similar atomic masses
B) Periodic repetition of outer electronic configuration
C) Similar densities
D) Similar nuclear charge
3. Which of the following is NOT a periodic property?
A) Ionization energy
B) Specific heat
C) Atomic size
D) Electronegativity
4. Atomic radius is measured as the distance between:
A) Nucleus and the nearest atom
B) Nucleus to outermost electron shell
C) Two nuclei in a molecule
D) Nucleus and first electron shell
5. Across a period, covalent atomic radius:
A) Increases
B) Decreases
C) Remains the same
D) Increases then decreases
6. Down a group, atomic radius:
A) Increases
B) Decreases
C) Remains same
D) Becomes zero
7. Which group shows sudden increase in atomic size due to van der Waals radius?
A) Group 1
B) Group 2
C) Group 17
D) Group 18
8. In Period 2, the correct atomic size order is:
A) Li > Be > B > C > N > O > F
B) Li > B > Be > C > O > F > N
C) Li > Be > B > C > O > N > F
D) Li > Be > B > N > O > F > C
9. Which has the largest radius?
A) Na+
B) Mg2+
C) F–
D) O2–
10. Among isoelectronic species, ionic radius decreases with:
A) Increase in nuclear charge
B) Decrease in nuclear charge
C) Increase in number of electrons
D) None of these
11. Ionization energy is the:
A) Minimum energy required to add an electron
B) Minimum energy to remove most loosely bound electron
C) Maximum energy to remove all electrons
D) Energy released when an electron is added
12. Ionization energy is expressed in:
A) kJ/mol only
B) eV/atom only
C) kcal/mol only
D) All of these
13. Which has the highest ionization energy?
A) He
B) Ne
C) F
D) Cl
14. Which has the lowest ionization energy?
A) Li
B) Cs
C) K
D) Na
15. Across a period, ionization energy generally:
A) Increases
B) Decreases
C) Remains constant
D) Fluctuates randomly
16. In second period, correct order of ionization energy is:
A) Li < B < Be < C < O < N < F < Ne
B) Li < Be < B < N < O < C < F < Ne
C) Li < Be < C < B < O < F < N < Ne
D) Li < B < Be < O < N < F < Ne < C
17. Electron affinity is:
A) Always positive
B) Always negative
C) Usually negative but may be positive
D) Zero
18. Which has the most negative electron affinity?
A) F
B) Cl
C) O
D) S
19. Which has the most positive electron affinity?
A) He
B) Ar
C) Ne
D) Kr
20. Electron affinity of noble gases is:
A) Negative
B) Zero
C) Positive
D) Infinite
21. Which is correct for halogens in electron affinity trend?
A) F > Cl > Br > I
B) Cl > F > Br > I
C) I > Br > Cl > F
D) Br > Cl > F > I
22. Electronegativity is a:
A) Dimensionless quantity
B) Measured in kJ/mol
C) Measured in eV/atom
D) Positive value in all cases
23. Who introduced the electronegativity scale in use today?
A) Pauling
B) Mendeleev
C) Moseley
D) Bohr
24. Highest electronegativity is of:
A) O
B) Cl
C) F
D) N
25. Which factor increases electronegativity?
A) Increase in atomic size
B) Increase in nuclear charge
C) Increase in metallic nature
D) Decrease in nuclear charge
26. If the electronegativity difference between two atoms is 1.7, the bond is:
A) 100% ionic
B) 50% ionic
C) 100% covalent
D) Metallic
27. Electron affinity can be experimentally measured but electronegativity:
A) Can also be experimentally measured
B) Cannot be experimentally measured
C) Is always greater
D) Is always smaller
28. Metallic character increases:
A) Across a period
B) Down a group
C) Diagonally in the table
D) Randomly
29. Non-metallic character increases:
A) Down a group
B) Across a period
C) Both across and down
D) Only in noble gases
30. Which group element has valency 0?
A) Group 17
B) Group 18
C) Group 1
D) Group 2
31. Metallic oxides are generally:
A) Basic
B) Acidic
C) Neutral
D) Amphoteric
32. Non-metallic oxides are generally:
A) Basic
B) Amphoteric
C) Acidic
D) Neutral
33. Across a period, the basic nature of oxides:
A) Increases
B) Decreases
C) Remains same
D) First increases then decreases
34. Down a group, oxides become:
A) More acidic
B) More basic
C) Neutral
D) Amphoteric
35. For metals, melting and boiling point generally:
A) Increase down the group
B) Decrease down the group
C) Remain constant
D) Become zero
36. Which is amphoteric oxide?
A) BeO
B) MgO
C) CO
D) SO3
37. Which is NOT amphoteric?
A) Zn
B) Al
C) Pb
D) Na
38. Which is the most electrovalent compound?
A) NaCl
B) KF
C) CsF
D) CaO
39. Which is the strongest base?
A) NaOH
B) KOH
C) LiOH
D) CsOH
40. Strongest basic oxide is:
A) Na2O
B) Cs2O
C) Li2O
D) MgO
41. Which oxide is neutral?
A) CO2
B) CO
C) SO3
D) N2O5
42. Which hydride is acidic?
A) NH3
B) H2O
C) HCl
D) PH3
43. Which hydride is neutral?
A) CH4
B) NH3
C) H2S
D) HCl
44. Which hydride is basic?
A) NH3
B) HF
C) HCl
D) H2S
45. Which is amphoteric metalloid?
A) Si
B) As
C) Ge
D) Sb
46. Which oxide forms H2SO4 with water?
A) SO2
B) SO3
C) CO2
D) N2O5
47. Which nitrogen oxide forms HNO3 only?
A) N2O
B) NO2
C) N2O3
D) N2O5
48. Which oxide forms H3PO3 with water?
A) P4O10
B) P4O6
C) N2O5
D) Cl2O7
49. Which forms HClO4 with water?
A) Cl2O
B) Cl2O3
C) Cl2O7
D) Cl2O5
50. Which element has both metallic and non-metallic properties?
A) C
B) Si
C) O
D) Na
Answer Key
1-B, 2-B, 3-B, 4-B, 5-B, 6-A, 7-D, 8-C, 9-C, 10-A,
11-B, 12-D, 13-A, 14-B, 15-A, 16-A, 17-C, 18-B, 19-C, 20-C,
21-B, 22-A, 23-A, 24-C, 25-B, 26-B, 27-B, 28-B, 29-B, 30-B,
31-A, 32-C, 33-B, 34-B, 35-B, 36-A, 37-D, 38-C, 39-D, 40-B,
41-B, 42-C, 43-A, 44-A, 45-A, 46-B, 47-D, 48-B, 49-C, 50-B
Here are 10 application-based questions from your given notes — these require students to use concepts rather than just recall facts:
1. Sodium oxide (Na₂O) reacts vigorously with water to form a strong alkali.
Explain why Na₂O shows this strong basic nature based on its metallic character and position in the periodic table.
2. Chlorine has a higher electron affinity than fluorine, even though fluorine is more electronegative.
Explain this apparent contradiction using atomic size and electron–electron repulsion concepts.
3. Between MgO and BeO, one is strongly basic while the other is amphoteric.
Identify each and explain the reason for this difference based on periodic trends.
4. Lithium forms Li₂O (strongly basic), while Beryllium forms BeO (amphoteric).
Explain the difference in the nature of their oxides using metallic and non-metallic character trends.
5. Among the following ions — F⁻, O²⁻, Na⁺, Mg²⁺ —
Arrange them in decreasing order of size and justify your answer using nuclear charge and isoelectronic species concept.
6. A bond between two atoms has an electronegativity difference of 0.5.
Predict the type of bond and give one real-life example of such a compound.
7. Phosphorus forms two oxides: P₄O₆ and P₄O₁₀.
State the nature (acidic/basic/amphoteric) of each and write the products when each reacts with water.
8. Caesium hydroxide (CsOH) is the strongest base among alkali metal hydroxides.
Explain why its basic strength is greater than NaOH using atomic size and bond strength arguments.
9. Nitrogen dioxide (NO₂) dissolves in water to give both HNO₂ and HNO₃.
Explain the oxidizing property of NO₂ based on the non-metallic nature trend.
10. Carbon dioxide (CO₂) is acidic, but carbon monoxide (CO) is neutral.
Explain this difference in terms of oxidation state of carbon and nature of oxides.
Here are 10 Competency-Based Questions (CBQs) based on your provided notes.
I’ve included case studies, data tables, and situations so students have to apply concepts rather than just recall them.
CFQ 1 – Trends in Atomic Radius
A part of the periodic table is shown below:
| Element | Li | Be | B | C | N | O | F | Ne |
|---|---|---|---|---|---|---|---|---|
| Atomic Radius (pm) | 152 | 112 | 88 | 77 | 74 | 66 | 64 | 62 |
Answer the following:
a) State the trend in atomic radius across Period 2.
b) Explain why the atomic radius decreases from Li to F.
c) Why is the decrease not uniform between Be and B?
d) Predict the atomic radius trend in Period 3 elements.
e) Which factor has a stronger effect here — nuclear charge or number of shells? Justify.
CFQ 2 – Ionization Energy Variations
The ionization energies of some elements are given:
| Element | Li | B | Be | C | O | N | F | Ne |
|---|---|---|---|---|---|---|---|---|
| I.E (kJ/mol) | 520 | 801 | 900 | 1086 | 1314 | 1402 | 1681 | 2081 |
a) Arrange these elements in order of increasing metallic character.
b) Why does Be have higher I.E than B?
c) Why does O have lower I.E than N?
d) Identify the most reactive non-metal from the list.
e) Which element will lose its electron most easily?
CFQ 3 – Electron Affinity and Reactivity
The electron affinity (E.A) values of halogens are:
| Element | F | Cl | Br | I |
|---|---|---|---|---|
| E.A (kJ/mol) | –328 | –349 | –324 | –295 |
a) Which halogen has the highest tendency to accept an electron?
b) Why is the E.A of Cl more negative than F?
c) Predict the reactivity trend of halogens based on E.A and electronegativity.
d) Which halogen would you expect to be the best oxidizing agent? Why?
e) Give one industrial use of this oxidizing property.
CFQ 4 – Nature of Oxides
Consider the following oxides: Na₂O, MgO, BeO, CO₂, SiO₂.
a) Classify each oxide as basic, acidic, or amphoteric.
b) Write the reaction of Na₂O with water.
c) Write the reaction of CO₂ with water.
d) Which oxide can react with both acid and base? Give its reaction with HCl.
e) Explain the trend in basic nature across the period from Na₂O to SiO₂.
CFQ 5 – Electronegativity and Bond Type
Electronegativity values:
Na = 0.93, Cl = 3.16, H = 2.20, O = 3.44, C = 2.55
a) Calculate the electronegativity difference between Na and Cl. Predict bond type.
b) Calculate the electronegativity difference between H and O. Predict bond type.
c) Which compound among NaCl, H₂O, and CH₄ will have the highest ionic character?
d) Which one will have purely covalent bonds?
e) Why does bond type change with electronegativity difference?
CFQ 6 – Metallic vs Non-Metallic Nature
The metallic character of elements decreases across a period.
a) Explain this trend in terms of ionization energy.
b) Between Na and Al, which is a better reducing agent? Why?
c) Between S and Cl, which forms more acidic oxide? Why?
d) Which will have more basic oxide — MgO or Na₂O? Justify.
e) Relate metallic character to nature of oxide formed.
CFQ 7 – Isoelectronic Species
Species: Na⁺, Mg²⁺, F⁻, O²⁻, N³⁻
a) Arrange them in decreasing order of size.
b) Explain the order using nuclear charge.
c) Which ion has the smallest radius? Why?
d) Which ion will have the weakest hold on its outer electrons?
e) Which one will show the strongest electrostatic attraction in compounds?
CFQ 8 – Amphoteric Behavior
BeO and Al₂O₃ are amphoteric oxides.
a) What does amphoteric mean?
b) Write a reaction of BeO with HCl.
c) Write a reaction of BeO with NaOH.
d) Why is MgO not amphoteric?
e) Which property of Be and Al leads to amphoterism?
CFQ 9 – Trends in Hydride Nature
Consider: LiH, NaH, AlH₃, CH₄, NH₃, H₂O, H₂S, HCl.
a) Identify the acidic hydrides.
b) Identify the basic hydrides.
c) Identify the neutral hydrides.
d) Explain why LiH behaves as a strong base.
e) Why is NH₃ basic but H₂S acidic?
CFQ 10 – Reactivity Extremes
In a period, reactivity is highest at both ends.
a) Why is reactivity high on the extreme left?
b) Why is reactivity high on the extreme right?
c) Which group’s reactivity is due to low ionization energy?
d) Which group’s reactivity is due to high electronegativity and electron affinity?
e) Give one real-world application of this difference in reactivity.
