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Chapter 9· Group Properties and Elements
MCQs with Answers 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 9 in your book, in the book's option order.
Q9.1 Group 17: Halogens
Which halogen will have the least reactivity with alkaline earth metals?
(a) Chlorine (b) Iodine (c) Bromine (d) Fluorine Show answer and reasoning Answer (b) Iodine
Step by step
F > Cl > Br > I. Why the others are wrong
(a) more reactive than Br and I.(c) more reactive than iodine.(d) the most reactive.Remember
Halogens: the lower, the lazier.
Q9.2 Transition Elements
Which compound do you expect to be coloured?
(a) KCl (b) BaCl₂ (c) AlCl₃ (d) NiCl₂ Show answer and reasoning Answer (d) NiCl₂
Step by step
Coloured compounds → transition metal. Only Ni is in groups 3-12. Why the others are wrong
(a) white (group 1).(b) white (group 2).(c) white (group 13).Remember
Colour = d-block.
Q9.3 Metals and Non-metals
In which element do there exist the strongest forces of attraction between atoms?
Show answer and reasoning Answer (a) Mg
Step by step
Same number of mobile electrons per atom. Smallest atom → strongest metallic bond. Why the others are wrong
(b) larger than Mg.(c) larger still.(d) the largest, weakest.Remember
Top of the group = strongest bonding.
Q9.4 Transition Elements
Elements of which group are all coloured?
(a) Second group (b) Sixth group (c) Fourth group (d) Fifth group Show answer and reasoning Answer (b) Sixth group
Step by step
Group 2: alkaline earth metals, white compounds. Groups 4, 5, 6 are transition groups. Group 6 compounds are the most consistently coloured. Why the others are wrong
(a) alkaline earth metals form white compounds.(c) titanium(IV) compounds are mostly white (TiO₂ is white paint).(d) vanadium compounds are coloured, but the key the book intends is group 6.Remember
Chromium = "chroma", colour.
Q9.5 Hydrogen Halides
Which halogen acid is unstable at room temperature?
Show answer and reasoning Answer (b) HI
Step by step
Bond energies: H–F 568, H–Cl 431, H–Br 366, H–I 299 kJ mol⁻¹. Why the others are wrong
(a) more stable than HI.(c) stable.(d) the most stable.Remember
Weakest bond → least stable.
Q9.6 Group 1: Alkali Metals
Which oxide is the most basic oxide?
(a) Na₂O (b) Li₂O (c) MgO (d) CO Show answer and reasoning Answer (a) Na₂O
Step by step
Na₂O + H₂O → 2NaOH, a strong alkali. Why the others are wrong
(b) Li is less metallic than Na.(c) group 2, less basic.(d) CO is a neutral oxide.Remember
More metallic metal → more basic oxide.
Q9.7 Group 1: Alkali Metals
Which group elements are the most reactive elements?
(a) Transition metal group (b) First group (c) Second group (d) Third group Show answer and reasoning Answer (b) First group
Step by step
One electron to lose, lowest ionisation energies. Why the others are wrong
(a) transition metals are fairly unreactive.(c) must lose two electrons.(d) less reactive.Remember
Group 1 = most reactive metals.
Q9.8 Oxidation, Reduction and Displacement
The following solutions of a halogen and a sodium halide are mixed. Which solution will turn dark because of a reaction?
(a) Br₂ and NaCl (b) Br₂ and NaF (c) Cl₂ and NaF (d) Cl₂ and NaI Show answer and reasoning Answer (d) Cl₂ and NaI
Step by step
Oxidising power: F₂ > Cl₂ > Br₂ > I₂. Only a higher halogen displaces a lower one. Why the others are wrong
(a) Br₂ is weaker than Cl₂: no reaction.(b) no reaction.(c) Cl₂ cannot displace F.Remember
Up displaces down.
Q9.9 Noble Gases
X is a monoatomic gas. Which statement about it is correct?
(a) X burns in air (b) X is coloured (c) X is unreactive (d) X will displace iodine from its compounds Show answer and reasoning Answer (c) X is unreactive
Step by step
Monoatomic gas → group 18 → complete outer shell → unreactive. Why the others are wrong
(a) they do not burn.(b) all colourless.(d) displacing iodine needs a reactive halogen.Remember
Single atoms = noble gas.
Q9.10 Group 1: Alkali Metals
Which property is correct for group 1 elements?
(a) Low catalytic activity (b) High density (c) Low electrical conductivity (d) High melting point Show answer and reasoning Answer (a) Low catalytic activity
Step by step
Check each: low density, good conductors, low melting points → (b), (c), (d) are false. Why the others are wrong
(b) Li, Na and K are lighter than water.(c) they are good conductors (metals).(d) they melt low (Cs at 28 °C).Remember
Group 1: light, soft, low-melting, good conductors, not catalysts.
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.
QB1 Group 1: Alkali Metals
Down group 1 the melting point:
(a) increases (b) stays the same (c) decreases (d) first decreases then increases Show answer and reasoning Answer (c) decreases
Step by step
Bigger atoms → weaker metallic bond → lower melting point. Why the others are wrong
(a) Wrong.(b) Wrong.(d) Wrong.Remember
Group 1: softer and lower-melting going down.
QB2 Group 1: Alkali Metals
Density increases down group 1 because:
(a) volume increases more than mass (b) atoms get smaller (c) mass increases more than volume (d) melting point rises Show answer and reasoning Answer (c) mass increases more than volume
Step by step
Density = mass ÷ volume. Why the others are wrong
(a) that would lower density.(b) atoms get bigger.(d) melting point falls.QB3 Group 1: Alkali Metals
Which alkali metal sinks in water?
Show answer and reasoning Answer (d) Rb
Step by step
Density of water = 1 g cm⁻³. Why the others are wrong
(a) 0.53, floats.(b) 0.97, floats.(c) 0.86, floats.Remember
Below K, they sink.
QB4 Group 17: Halogens
At room temperature bromine is a:
(a) pale yellow gas (b) yellow-green gas (c) red-brown liquid (d) grey-black solid Show answer and reasoning Answer (c) red-brown liquid
Step by step
F₂ gas, Cl₂ gas, Br₂ liquid, I₂ solid. Why the others are wrong
(a) fluorine.(b) chlorine.(d) iodine.Remember
Gas, gas, liquid, solid going down.
QB5 Group 17: Halogens
The melting and boiling points of halogens increase down the group because:
(a) larger molecules with more electrons attract each other more strongly (b) reactivity increases (c) they become ionic (d) the bonds inside the molecules get stronger Show answer and reasoning Answer (a) larger molecules with more electrons attract each other more strongly
Step by step
Bigger molecule → stronger intermolecular forces → higher m.p./b.p. Why the others are wrong
(b) reactivity decreases.(c) they stay covalent X₂.(d) the X–X bond is not what melts.Remember
Bigger halogen molecule = stickier.
QB6 Oxidation, Reduction and Displacement
Oxidation is:
(a) gain of electrons (b) loss of neutrons (c) gain of protons (d) loss of electrons Show answer and reasoning Answer (d) loss of electrons
Step by step
OIL RIG: oxidation is loss, reduction is gain. Why the others are wrong
(a) that is reduction.(b) Wrong.(c) Wrong.QB7 Oxidation, Reduction and Displacement
In Cl₂ + 2e⁻ → 2Cl⁻, chlorine acts as:
(a) a reducing agent (b) an oxidising agent (c) a catalyst (d) an acid Show answer and reasoning Answer (b) an oxidising agent
Step by step
Accepts electrons → oxidising agent. Why the others are wrong
(a) reducing agents give electrons.(c) Wrong.(d) Wrong.Remember
The agent is the opposite of what happens to it.
QB8 Oxidation, Reduction and Displacement
The order of oxidising power of halogens is:
(a) Cl₂ > Br₂ > I₂ (b) I₂ > Br₂ > Cl₂ (c) Br₂ > Cl₂ > I₂ (d) all equal Show answer and reasoning Answer (a) Cl₂ > Br₂ > I₂
Step by step
Smaller atom grabs electrons more strongly. Why the others are wrong
(b) reversed.(c) Wrong.(d) Wrong.Remember
Same order as reactivity.
QB9 Hydrogen Halides
The thermal stability of hydrogen halides:
(a) increases down the group (b) is the same for all (c) decreases down the group (d) is highest for HI Show answer and reasoning Answer (c) decreases down the group
Step by step
Longer bond → weaker bond → less stable. Why the others are wrong
(a) Wrong.(b) Wrong.(d) lowest.Remember
HF toughest, HI weakest.
QB10 Transition Elements
Which catalyst is used in the Haber process?
(a) Vanadium pentoxide (b) Nickel (c) Platinum (d) Iron Show answer and reasoning Answer (d) Iron
Step by step
Haber: Fe. Why the others are wrong
(a) Contact process.(b) margarine.(c) older Contact process, converters.Remember
Haber = iron (Fe for fertiliser).
QB11 Transition Elements
V₂O₅ replaced platinum in the Contact process mainly because platinum:
(a) is too cheap (b) is poisoned (made inactive) by arsenic impurity and is expensive (c) does not adsorb gases (d) is not a transition metal Show answer and reasoning Answer (b) is poisoned (made inactive) by arsenic impurity and is expensive
Step by step
2SO₂ + O₂ ⇌ 2SO₃ (V₂O₅). Why the others are wrong
(a) it is expensive.(c) it adsorbs gases well.(d) it is one.Remember
Arsenic poisons platinum.
QB12 Transition Elements
Which is NOT a property of transition elements?
(a) high densities (b) variable oxidation states (c) colourless compounds only (d) catalytic activity Show answer and reasoning Answer (c) colourless compounds only
Step by step
Their compounds are typically coloured. Why the others are wrong
(a) this is a real property of transition elements, so it is not the answer.(b) this is a real property of transition elements, so it is not the answer.(d) this is a real property of transition elements, so it is not the answer.Remember
Transition = colour.
QB13 Noble Gases
Noble gases are unreactive because they:
(a) have complete outer shells (b) are very heavy (c) are liquids (d) form diatomic molecules Show answer and reasoning Answer (a) have complete outer shells
Step by step
Full shell → no tendency to lose, gain or share. Why the others are wrong
(b) helium is very light.(c) gases.(d) monoatomic.Remember
Full shell = no need to react.
QB14 Metals and Non-metals
The only non-metal that conducts electricity is:
(a) sulphur (b) iodine (c) phosphorus (d) graphite Show answer and reasoning Answer (d) graphite
Step by step
Graphite: one mobile electron per carbon. Why the others are wrong
(a) Wrong.(b) lustrous, but does not conduct.(c) Wrong.Remember
Pencil lead conducts.
