Learners' Alley, The Periodic Table and Periodicity slides
2
Which Period 3 element has the highest melting point?
AMg
BAl
CSi
DS
Answer [1]
Learners' Alley, The Periodic Table and Periodicity slides
3
Which oxide reacts with both hydrochloric acid and aqueous sodium hydroxide?
AMgO
BAl2O3
CSiO2
DP4O10
Answer [1]
Learners' Alley, The Periodic Table and Periodicity slides
4
Which statement about the Group 2 elements, magnesium to barium, is correct?
AReducing power decreases down the group.
BThe ionic radius increases down the group.
CElectronegativity increases down the group.
DReactivity with water decreases down the group.
Answer [1]
Learners' Alley, The Periodic Table and Periodicity slides
5
Astatine is below iodine in Group 17. Which statement is correct?
AAstatine displaces iodine from potassium iodide.
BChlorine displaces astatine from sodium astatide.
CAstatine is a gas at room temperature.
DAstatine is more reactive than chlorine.
Answer [1]
Learners' Alley, The Periodic Table and Periodicity slides
6
Which metal oxide is not reduced by heating with carbon?
Acopper(II) oxide
Blead(II) oxide
Cmagnesium oxide
Dzinc oxide
Answer [1]
Learners' Alley, The Periodic Table and Periodicity slides
7
(a)
Explain why Mg2+ (0.065 nm) is much smaller than a Mg atom (0.160 nm).
[2]
(b)
Explain why the first ionisation energy of sulfur is lower than that of phosphorus.
[2]
Learners' Alley, The Periodic Table and Periodicity slides
8
(a)
Why does aluminium conduct electricity better than sodium?
[1]
(b)
Why is the melting point of sulfur higher than that of chlorine?
[1]
Learners' Alley, The Periodic Table and Periodicity slides
9
(a)
Explain why Na2O gives an alkaline solution but SO3 gives an acidic one.
[2]
(b)
Element X is a solid of low conductivity. Its only chloride is a liquid that does not conduct, and reacts with water to give a white solid and a strongly acidic solution. Identify X.
[1]
Learners' Alley, The Periodic Table and Periodicity slides
10
Write the equation for rubidium reacting with water, and name the products.
[2]
Learners' Alley, The Periodic Table and Periodicity slides
11
Which decomposes at a lower temperature, calcium carbonate or barium carbonate? Explain.
[2]
Learners' Alley, The Periodic Table and Periodicity slides
12
(a)
Describe and explain what you see when bromine water is added to potassium iodide solution.
[2]
(b)
Why is HI less thermally stable than HCl?
[1]
Learners' Alley, The Periodic Table and Periodicity slides
13
(a)
Excess zinc powder is added to blue copper(II) sulfate solution. Describe what you see and write the ionic equation.
[2]
(b)
Tin is between iron and lead in the reactivity series. Suggest how tin is extracted from tin(II) oxide.
[1]
Learners' Alley, The Periodic Table and Periodicity slides
14
(a)
Why does a scratched galvanised bucket not rust, while a scratched tin can does?
[2]
(b)
How is rusting prevented on the parts of a steel pier under water?
[1]
Learners' Alley, The Periodic Table and Periodicity slides
B
Practice
17 marks
15
What increases from Na to Ar across Period 3?
Adensity
Bmelting point
Cnon-metallic character
Dthe number of electron shells
Answer [1]
2024 BMSS O Prelim P1 Q25
16
Which statement describes a trend going from left to right across Period 3?
AThe ability of the elements to conduct electricity increases.
BThe number of neutrons in the atom increases.
CThe number of valence electrons decreases.
DThe tendency to gain electrons increases.
Answer [1]
2024 BTYSS FYE O EOY P1 Q25
17
Magnesium and chlorine are both in Period 3. Which statement best explains why magnesium has more metallic character than chlorine?
AMagnesium has fewer electrons than chlorine.
BMagnesium has fewer electron shells than chlorine.
CMagnesium has fewer protons than chlorine.
DMagnesium has fewer valence electrons than chlorine.
Answer [1]
2022 SJI O Prelim P1 Q21
18
Group 1 elements react with water. Which row describes the products and the trend in reactivity?
products
trend in reactivity
A
metal hydroxide and hydrogen
less reactive down the group
B
metal hydroxide and hydrogen
more reactive down the group
C
metal oxide and hydrogen
less reactive down the group
D
metal oxide and hydrogen
more reactive down the group
Arow A
Brow B
Crow C
Drow D
Answer [1]
2024 SKSS O Prelim P1 Q27
19
Which statements about the elements in Group 1 are true?
I They are soft and can be cut easily. II They are oxidising agents. III The melting point decreases down the group. IV The reactivity decreases down the group.
AI and II
BI and III
CII and IV
DI, II and III
Answer [1]
2024 PLMGSS O Prelim P1 Q34
20
Rubidium is in the same group as sodium. Which statement about rubidium is not correct?
AIt forms ionic bonds with halogens.
BIt forms rubidium hydroxide when it reacts with water.
CIt reacts more explosively with water than sodium.
DIts melting point is higher than that of sodium.
Answer [1]
2024 Dunman O Prelim P1 Q26
21
Which statement is correct?
AGroup 1 elements are less reactive than the Group 2 element in the same period because they only need to lose one electron to have complete shells.
BGroup 1 elements are stored under oil to avoid reaction with oxygen and water in the air.
CGroup 1 elements become more reactive down the group because the number of outer shell electrons increases.
DThe melting point of Group 1 elements decreases down the group because there is more attraction between positive ions and the delocalised electrons.
Answer [1]
2024 ANDSS O Prelim P1 Q27
22
How do the atomic radius and the strength of the forces between molecules change going down Group 17?
atomic radius
strength of forces between molecules
A
decrease
decrease
B
decrease
increase
C
increase
decrease
D
increase
increase
Arow A
Brow B
Crow C
Drow D
Answer [1]
2021 SJI O Prelim P1 Q7
23
Which property of the halogens decreases down Group 17?
Aability as an oxidising agent
Bboiling point
Ccolour intensity
Ddensity
Answer [1]
2023 CGSS O Prelim P1 Q25
24
The reactivity of the halogens decreases down the group. Which statement explains this?
ADecreasing distance between the nucleus and the outer shell makes it easier for the atom to attract electrons.
BIncreasing distance between the nucleus and the outer shell makes it easier for the atom to attract electrons.
CDecreasing distance between the nucleus and the outer shell makes it harder for the atom to attract electrons.
DIncreasing distance between the nucleus and the outer shell makes it harder for the atom to attract electrons.
Answer [1]
2024 Whitley O Prelim P1 Q27
25
Elements P and Q are in Group 17. P is a liquid and Q is a solid at room temperature. Which statement is correct?
AAtoms of P have more electron shells than atoms of Q.
BMolecules of Q have more atoms than molecules of P.
CP is a stronger oxidising agent than Q.
DQ displaces P from an aqueous solution of P.
Answer [1]
2024 AES O Prelim P1 Q26
26
A halogen reacts with a solution containing bromide ions: X2 + 2Br−(aq) → 2X−(aq) + Br2(aq). Which row is true?
X2
colour change
A
chlorine
orange to colourless
B
chlorine
colourless to orange
C
iodine
orange to colourless
D
iodine
colourless to orange
Arow A
Brow B
Crow C
Drow D
Answer [1]
2024 BBSS O Prelim P1 Q16
27
A solution of a lithium halide and a halogen are mixed. A reaction occurs and the mixture darkens. What are the reactants?
Abromine and lithium chloride
Biodine and lithium fluoride
Cchlorine and lithium iodide
Dchlorine and lithium fluoride
Answer [1]
2024 SCGS O Prelim P1 Q21
28
Astatine is below iodine in Group 17. Which row describes astatine?
state at room temperature
reactivity
A
gas
does not displace chlorine, bromine or iodine
B
gas
displaces iodine but not chlorine or bromine
C
solid
does not displace chlorine, bromine or iodine
D
solid
displaces iodine but not chlorine or bromine
Arow A
Brow B
Crow C
Drow D
Answer [1]
2024 CHS O Prelim P1 Q26
29
Alkali metals and halogens react readily to form salts. Which pair reacts most vigorously?
alkali metal
halogen
A
lithium
fluorine
B
lithium
iodine
C
potassium
fluorine
D
potassium
iodine
Arow A
Brow B
Crow C
Drow D
Answer [1]
2026 St Patrick's School O MYE P1-P3 Q5
30
Which statement about the elements in Group 18, helium to xenon, is correct?
AArgon reacts with iron to form a compound.
BHelium is less dense than air.
CThe elements change from gas to solid down the group.
DThe elements exist as covalent molecules.
Answer [1]
2023 Catholic High School O Prelim P1 Q25
31
Which statement about the elements in Group 18 is correct?
AAtoms of the elements are held together by weak covalent bonds.
BGoing down the group, the number of electrons in the atom increases by eight for each element.
CThe outer shell of each noble gas is fully filled with electrons.
DThey are coloured gases at room temperature.
Answer [1]
2026 Dunman O Prelim P1 Q24
Learners' AlleyDesigned by Khow Willard
08
The Periodic Table and Periodicity
Set AAnswer key
A
From the lesson
28 marks
1
CP3−[1]
The anions have one more shell than the cations.
Of the anions, P3− has the fewest protons pulling on its 18 electrons, so it is the largest (0.212 nm).
2
CSi[1]
Silicon has a giant covalent structure: very many strong covalent bonds must break.
Mg and Al are metallic, and S is simple molecular.
3
BAl2O3[1]
Aluminium oxide is amphoteric.
MgO is basic, and SiO2 and P4O10 are acidic.
4
BThe ionic radius increases.[1]
Each ion down the group has one more shell, so it is larger.
Reducing power and reactivity increase down the group, and electronegativity decreases.
5
BChlorine displaces astatine.[1]
Reactivity decreases down the group, so chlorine is more reactive and displaces astatine.
Melting points increase down the group, so astatine is a solid.
6
Cmagnesium oxide[1]
Magnesium is above carbon in the reactivity series.
It is extracted by electrolysis. The other three metals are below carbon.
7
(a)
Mg2+ has lost its outer (third) shell.
The same 12 protons pull on 10 electrons instead of 12.[2]
(b)
The electron removed from S is paired in a 3p orbital.
Repulsion between the paired electrons makes it easier to remove.[2]
8
(a)
Each Al atom gives 3 delocalised electrons and each Na atom only 1, so there are more mobile charge carriers.[1]
(b)
S8 molecules have more electrons than Cl2, so the instantaneous dipole–induced dipole forces are stronger.[1]
9
(a)
Na2O is ionic: Na2O + H2O → 2NaOH.
SO3 is covalent: SO3 + H2O → H2SO4.[2]
(b)
Silicon (its chloride is SiCl4).[1]
10
2Rb + 2H2O → 2RbOH + H2
Rubidium hydroxide and hydrogen.[2]
11
Calcium carbonate.
Ca2+ is smaller, so it has a higher charge density and polarises the carbonate ion more, weakening its C–O bonds.[2]
12
(a)
The colourless solution turns brown.
Bromine is more reactive and displaces iodine: Br2 + 2KI → 2KBr + I2.[2]
(b)
The H–I bond (299 kJ mol−1) is weaker than H–Cl (431 kJ mol−1).[1]
13
(a)
Red-brown copper forms and the blue colour fades.
Zn + Cu2+ → Zn2+ + Cu[2]
(b)
Heat it with carbon: 2SnO + C → 2Sn + CO2.[1]
14
(a)
Zinc is more reactive than iron, so it corrodes instead of the iron.
Tin is less reactive than iron, so it only works as a barrier.[2]
(b)
Attach blocks of zinc or magnesium (sacrificial protection).[1]
B
Practice
17 marks
15
Cnon-metallic character[1]
The elements change from metals to non-metals across the period.
All have three shells, and melting point rises to silicon and then falls.
16
DThe tendency to gain electrons increases.[1]
The nuclear charge rises with the same shielding, so the atoms attract electrons more strongly.
Conductivity falls after aluminium, and the number of valence electrons increases.
17
Dfewer valence electrons[1]
With only two valence electrons, magnesium loses electrons easily to form a positive ion, which is metallic behaviour.
Both have three shells. Having fewer electrons or protons overall is not the reason.
18
Brow B[1]
2M + 2H2O → 2MOH + H2: a hydroxide and hydrogen.
The valence electron is lost more easily down the group, so reactivity increases.
19
BI and III[1]
Group 1 metals are soft and their melting points decrease down the group.
They lose electrons, so they are reducing agents, and their reactivity increases down the group.
20
DIts melting point is higher.[1]
Melting points decrease down Group 1, so rubidium melts at a lower temperature than sodium.
A, B and C follow from the group trends.
21
Bstored under oil[1]
Group 1 metals react with oxygen and water in air, so they are kept under oil.
Losing one electron is easier, so they are more reactive than Group 2. All have one outer electron, and the melting point falls because the attraction gets weaker.
22
Drow D[1]
Each halogen down the group has one more shell, so its atoms are larger.
Its molecules have more electrons, so the forces between them are stronger and the boiling points rise.
23
Aability as an oxidising agent[1]
The incoming electron is further from the nucleus and more shielded, so the halogen gains it less easily.
Boiling point, colour intensity and density all increase down the group.
24
Dincreasing distance, harder to attract[1]
Down the group the outer shell is further from the nucleus, so an incoming electron is attracted less strongly.
A halogen reacts by gaining an electron, so it becomes less reactive.
25
CP is the stronger oxidising agent.[1]
P is bromine and Q is iodine. Bromine is above iodine, so it is the stronger oxidising agent.
Iodine atoms have more shells, both are diatomic, and iodine cannot displace bromine.
26
Brow B[1]
Only a halogen above bromine can displace it, so X2 is chlorine.
Bromine forms, so the colourless solution turns orange.
27
Cchlorine and lithium iodide[1]
Chlorine is above iodine, so it displaces brown iodine from lithium iodide.
In A, B and D the halogen is below the halide, so nothing happens.
28
Crow C[1]
Melting points rise down the group, so astatine is a solid.
It is the least reactive of these halogens, so it displaces none of them.
29
Crow C[1]
Group 1 gets more reactive down the group, so potassium is the more reactive metal.
Group 17 gets less reactive down the group, so fluorine is the more reactive halogen.
30
BHelium is less dense than air.[1]
Helium is used in balloons because it is less dense than air.
The noble gases are unreactive, all gases at room temperature, and exist as single atoms.
31
Cfull outer shells[1]
Their outer shells are full, which is why they are unreactive.
They exist as single atoms, they are colourless, and the number of electrons does not always rise by eight (argon 18, krypton 36).
