Chapter 8: Periodic Table and PeriodicityMCQs with Answers
All 24 MCQs of 9th Class Chemistry Chapter 8, Periodic Table and Periodicity, with answers and the reason each option is right or wrong: the 10 textbook exercise MCQs plus 14 more board-style MCQs. Punjab Board new syllabus.
Try each one first: tap an option to check it, then read the reasoning and why the others are wrong.
A note about the questions
The wording follows published solved exercises and every answer was re-checked by hand, so the wording or the order of options may differ slightly from your print.
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Set A: Textbook exercise 10 MCQs
The multiple-choice questions at the end of Chapter 8 in your book, in the book's option order.
Q8.1Groups, Periods and Blocks
In which period and group will you place the element which is an important part of the solar cell?
Answer(a) Third period and 14th group
Step by step
Si: 1s² 2s² 2p⁶ 3s² 3p².
n = 3 → period 3; 3s²3p² → group 14.
Why the others are wrong
(b) that is carbon.
(c) that is phosphorus.
(d) that is sulphur.
Remember
Solar cell = silicon, just below carbon.
Q8.2Groups, Periods and Blocks
Identify the electronic configuration of the outermost shell of a transition metal.
Answer(b) ndˣns²
Step by step
ns²np⁴ = group 16; ns²np⁶ = group 18; ns²np⁵ = group 17.
d-subshell filling = transition metal.
Why the others are wrong
(a) oxygen family (group 16).
(c) noble gases (group 18).
(d) halogens (group 17).
Remember
A d in the configuration = transition metal.
Q8.3Metallic Character, Reactivity and Density
Which is the softest metal?
Answer(a) Na
Step by step
One mobile electron per atom → weak metallic bond → soft.
Why the others are wrong
(b) two electrons per atom, harder.
(c) three electrons per atom.
(d) a hard transition metal.
Remember
Alkali metals cut like butter.
Q8.4Properties within a Group
A yellow solid element exists in allotropic forms and is also present in fossil fuels. Indicate the name.
Answer(d) Sulphur
Step by step
Yellow + allotropes + in fossil fuels → sulphur.
Why the others are wrong
(a) carbon is black (graphite) or colourless (diamond).
(b) iodine is a violet-black solid.
(c) a silvery metal.
Remember
Yellow = sulphur.
Q8.5Properties within a Group
How many electrons can nitrogen accept in its outermost shell?
Answer(b) 3
Step by step
8 − 5 = 3.
Why the others are wrong
(a) that is oxygen.
(c) that is carbon's need.
(d) that is how many it has.
Remember
Electrons accepted = 8 − group electrons.
Q8.6Electron Affinity and Electronegativity
Which element is the most reactive element?
Answer(c) Fluorine
Step by step
Top right of the table (excluding noble gases) = most reactive non-metal.
Why the others are wrong
(a) reactive, but less than fluorine.
(b) below F in group 17, less reactive.
(d) N₂ is quite unreactive (triple bond).
Remember
F tops every non-metal list.
Q8.7Metallic Character, Reactivity and Density
Which element has the highest melting point?
Answer(a) Na
Step by step
Smallest atom → strongest metallic bond → highest melting point.
Why the others are wrong
(b) 63 °C.
(c) 39 °C.
(d) 28 °C, it melts in a warm hand.
Remember
Group 1: melting point falls down the group.
Q8.8Metallic Character, Reactivity and Density
In what order does the metallic character change in the second group?
Answer(d) Ba > Sr > Ca > Mg
Step by step
Down the group: Mg → Ca → Sr → Ba.
Metallic character rises the same way.
Why the others are wrong
(a) reversed and jumbled.
(b) Sr and Ba swapped.
(c) jumbled.
Remember
Lowest in the group = most metallic.
Q8.9Atomic Radius
Which of the following best describes the correct order of oxygen, fluorine and nitrogen's atomic radii?
Answer(c) F < O < N
Step by step
Left to right: N, O, F.
Radius falls: 75 > 73 > 71 pm.
Why the others are wrong
(a) F is the smallest.
(b) reversed.
(d) reversed.
Remember
Further right = smaller.
Q8.10Ionization Energy
The element having less value of ionization energy and less value of electron affinity is likely to belong to:
Answer(a) Group 1
Step by step
IE and EA both increase left to right.
Leftmost group: lowest of both.
Why the others are wrong
(b) higher than group 1.
(c) high values.
(d) the highest electron affinities.
Remember
Both low = far left.
Set B: More MCQs from this chapter 14 MCQs
Extra questions on the same ideas, of the kind set in board papers and class tests.
QB1Modern Periodic Table
The modern periodic table is based on:
Answer(b) atomic number
Step by step
Moseley: atomic number.
Why the others are wrong
(a) Mendeleev's basis.
(c) Wrong.
(d) Wrong.
Remember
Modern = Moseley = number.
QB2Modern Periodic Table
The number of groups and periods in the modern periodic table are:
Answer(c) 18 groups, 7 periods
Step by step
Columns: 18. Rows: 7.
Why the others are wrong
(a) reversed.
(b) old short form.
(d) Wrong.
Remember
More columns than rows.
QB3Groups, Periods and Blocks
The number of elements in the fourth period is:
Answer(d) 18
Step by step
Period 4 fills 4s, 3d, 4p: 2 + 10 + 6 = 18.
Why the others are wrong
(a) period 1.
(b) periods 2 and 3.
(c) periods 6 and 7.
Remember
2, 8, 8, 18, 18, 32, 32.
QB4Groups, Periods and Blocks
The lanthanide series starts after:
Answer(b) lanthanum (57)
Step by step
After La: lanthanides; after Ac: actinides.
Why the others are wrong
(a) actinides start there.
(c) Wrong.
(d) Wrong.
Remember
Lanthanides after lanthanum.
QB5Groups, Periods and Blocks
Elements of groups 13 to 18 are called:
Answer(c) p-block
Step by step
Block = subshell being filled.
Why the others are wrong
(a) groups 1-2.
(b) groups 3-12.
(d) the two bottom rows.
Remember
Right side = p.
QB6Properties within a Group
Elements in the same group show similar chemical properties because they have:
Answer(d) the same number of electrons in the outermost shell
Step by step
Same valence electrons → same kind of reactions.
Why the others are wrong
(a) Wrong.
(b) that is a period.
(c) Wrong.
Remember
Group = same outer electrons.
QB7Properties within a Group
The charge on the ion formed by a group 2 element is:
Answer(b) 2+
Step by step
Two outer electrons lost → 2+.
Why the others are wrong
(a) group 1.
(c) that is group 16.
(d) group 17.
Remember
Metal charge = group number (1, 2, 3).
QB8Properties within a Group
Down group 17 the reactivity of halogens:
Answer(a) decreases
Step by step
Halogens react by gaining an electron.
Bigger atom → gains less easily.
Why the others are wrong
(b) that is group 1.
(c) Wrong.
(d) Wrong.
Remember
Metals: more reactive down; non-metals: less.
QB9Atomic Radius
The distance between the nuclei of two bonded carbon atoms is 154 pm. The atomic (covalent) radius of carbon is:
Answer(c) 77 pm
Step by step
r = d ÷ 2 = 77 pm.
Why the others are wrong
(a) that is the whole bond length.
(b) doubled.
(d) a quarter.
Remember
Half the bond length.
QB10Atomic Radius
Down a group the atomic radius:
Answer(d) increases
Step by step
More shells → bigger atom.
Why the others are wrong
(a) that happens across a period.
(b) Wrong.
(c) Wrong.
Remember
Down = bigger.
QB11Ionization Energy
The first ionisation energy of sodium is +496 kJ mol⁻¹. This means:
Answer(b) 496 kJ is needed to remove one electron from each atom in one mole of gaseous Na atoms
Step by step
Removing an electron always needs energy.
Why the others are wrong
(a) it is absorbed, not released.
(c) that is electron affinity.
(d) Wrong.
Remember
IE is always positive.
QB12Ionization Energy
The second ionisation energy of magnesium (1450 kJ mol⁻¹) is higher than the first (737 kJ mol⁻¹) because:
Answer(a) the second electron is removed from a positive ion
Step by step
Mg → Mg⁺: 737 kJ.
Mg⁺ → Mg²⁺: 1450 kJ.
Why the others are wrong
(b) both are in the same shell.
(c) Mg²⁺ is smaller.
(d) Wrong.
Remember
Taking from a + ion is harder.
QB13Electron Affinity and Electronegativity
Which halogen has the highest electron affinity?
Answer(c) Cl
Step by step
Compare the table values: Cl is the largest release.
