AQA A Level Chemistry

Topic Questions

2.1 Periodicity

11 mark

Sodium sulfide, Na2S, is a reactive yellow solid, produced when sodium and sulfur react together.

How does the ionic radius of sodium compare with that of sulfur?

  • The ions have the same ionic radii

  • The atoms have the same atomic radii

  • Sodium < sulfur

  • Sodium > sulfur

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21 mark

The trends in three physical properties of the elements of Period 3 are shown in the graphs below.

UX5_lMDK_16

V-nM-xW0_17

18

Which physical property is not illustrated?

  • first ionisation energy

  • atomic radius

  • melting point

  • electrical conductivity

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31 mark

What is the correct classification for the element zirconium, Zr?

  • s block

  • d block

  • f block

  • p block

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41 mark

Which Period 3 element has the highest melting point?

  • Sulfur

  • Argon

  • Silicon

  • Aluminium

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51 mark

What is the correct equation for the second ionisation energy of rubidium, Rb?

  • Rb+ (g) → Rb2+ (g) + e-

  • Rb (g) → Rb+ (g) + e-

  • Rb2+ (g) → Rb3+ (g) + e-

  • Rb2+ (g) + e- → Rb+ (g)

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61 mark

Which statement is not correct for Group 2 metals?

  • An unpaired electron is present in the s orbital

  • Chemical reactivity increases with increasing atomic number

  • The first ionisation energy decreases with increasing atomic number

  • Atomic radius increases with increasing atomic number

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71 mark

Which Period 2 element from sodium to silicon, has the largest atomic radius?

  • magnesium

  • sodium

  • silicon

  • aluminium

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81 mark

The trend in melting points of some Period 3 elements can be represented as:

S8 > P4 > Cl2

What intermolecular force explains this trend in melting points?

  • permanent dipole-dipole

  • covalent bonding

  • hydrogen bonding

  • van der Waals

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91 mark

Why does aluminium have a higher melting point than magnesium?

  • aluminium has its valence electron in the p orbital

  • lower charge on the cation and increasing number of delocalised electrons

  • higher charge on the cation and increasing number of delocalised electrons

  • higher charge on the cation and increasing number of localised electrons

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101 mark

Why is the first ionisation energy of magnesium higher than the second ionisation energy?

  • less shielding

  • ionic radius increases

  • nuclear charge is increasing

  • greater attraction between positive nucleus and outer electron

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11 mark

Which of these elements has the third lowest first ionisation energy in its period and the third smallest atomic radius in its group?

  • Magnesium

  • Gallium

  • Potassium

  • Calcium

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21 mark

The graph shows the first ionisation energies of four consecutive elements. 

One of the elements reacts with hydrogen to form a covalent compound with formula HX. 

Which element could be X?

UHSpCDqM_24

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31 mark

The successive ionisation energies for element R are shown.

 

1st

2nd

3rd

4th

5th

6th

Ionisation energy / kJ mol-1

950

1800

2700

4800

6000

12 300

What is the oxidation state of element R when bonded to chlorine?

  • +1

  • +2

  • +3

  • +4

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41 mark

Element Q reacts with sulfur. The first five successive ionisation energies for element Q are shown.

 

1st

2nd

3rd

4th

5th

Ionisation energy value / kJ mol−1

738

1450

7733

10543

13630

What is the formula of the compound when element Q reacts with sulfur?

  • QS

  • QS3

  • Q3S

  • Q2S

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51 mark

The species Cl -, K+ and Ar are isoelectronic. This means that they have the same number of electrons.

In which order do their radii decrease?

 

largest     rightwards arrow     smallest

A

K+

Cl -

Ar

B

Cl -

Ar

K+

C

K+

Ar

Cl -

D

Ar

K+

Cl -

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61 mark

Which statement about energy levels and electrons is correct?

  • 18 is the maximum number of electrons in the 4th energy level

  • 10 is the maximum number of electrons in one d orbital

  • Yttrium is the first element with an electron in an f subshell

  • In a main energy level, the subshell with the highest energy is f

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71 mark

How many electrons are removed from 2.02 × 10−2 g of Ne (g) atoms to form Ne+ (g) ions?

  • 2.46 x 1023

  • 1.22 × 1022

  • 6.02 × 1020

  • 1.22 × 1021

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81 mark

Which of the following pairs does the second element have a higher 1st ionisation energy than the first element?

 

First element

Second element

A

Mg

Al

B

N

O

C

Ne

Na

D

K

Na

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91 mark

Element J has a lower first ionisation energy and higher melting point than the element preceding it in the periodic table. 

Its ion is isoelectronic with argon. 

What is the identity of element J?

  • Na

  • S

  • P

  • Al

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101 mark

The successive ionisation energies for element X are shown.

Ionisation 

Ionisation energy / kJ mol-1

1st

578

2nd

1817

3rd

2745

4th

11 577

5th

14 842

6th

18 379

What is the electron configuration for element X?

  • [Ne] 3s1

  • [Ne] 3s13p2

  • [Ne] 3s23p1

  • [Ne] 3s23p2

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11 mark

What is the correct order of the decreasing melting points of these period 3 chlorides shown?

 

highest melting point     rightwards arrow     lowest melting point

A

SiCl4

PCl3

NaCl

MgCl2

B

MgCl2

NaCl

SiCl4

PCl3

C

NaCl

MgCl2

PCl3

SiCl4

D

NaCl

MgCl2

SiCl4

PCl3

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21 mark

Consecutive elements X, Y and Z, are in the third period of the periodic table. Element Y has the highest first ionisation energy and the lowest melting point of these three elements.

What could be the identities of X, Y and Z?

  • silicon, phosphorus, sulfur

  • sodium, magnesium, aluminium

  • aluminium, silicon, phosphorus

  • magnesium, aluminium, silicon

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31 mark

Which graph correctly shows the relative melting points of period 3 elements plotted against their relative electronegativities?

  • FsovnU2-_19

  • Xwi40r6c_20

  • _7rqM5eI_21

  • rFwEzgq-_22

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41 mark

Period 3 elements Q and R react together to form compound S.

Element Q has the second smallest atomic radius in period 3.

Apart from argon, there is only one element in period 3 which has a lower melting point than element R.

Which compound could be S?

  • Li2S

  • CaS

  • PCl3

  • MgCl2

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51 mark

Period 3 elements can react with chlorine to produce the following chlorides:

MgCl2       AlCl3      SiCl4      PCl3      SCl2

Period 3 elements also react with oxygen to produce oxides.

Which of the elements have a higher oxidation state in their oxides than in the above chlorides?

  • P and S

  • Mg, P and S

  • Mg and P

  • Mg, Al, Si, P and S

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61 mark

The second ionisation energy of calcium is 1145 kJ mol-1.

Which equation correctly represents this statement?

  • Ca+(g) → Ca2+(g) + e-          ΔH = -1145 kJ mol-1

  • Ca(g) → Ca2+(g) + 2e-          ΔH = +1145 kJ mol-1

  • Ca+(g) → Ca2+(g) + e-         ΔH  = +1145 kJ mol-1

  • Ca(g) → Ca+(g) + e-            ΔH = -1145 kJ mol-1

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71 mark

The first six ionisation energies of an element in period 3 are shown below.

 

1st

2nd

3rd

4th

5th

6th

Ionisation energy kJ mol-1

787

1577

3232

4356

16 091

19 805

What is the identity of the period 3 element?

  • Chlorine

  • Phosphorus

  • Carbon

  • Silicon

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81 mark

An element in the d block of the periodic table forms a +4 ion and has the electron configuration of [Ar] 3d1.

What is the identity of the element?

  • Chromium

  • Copper

  • Vanadium

  • Silicon

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91 mark

Electron configurations for atoms of different elements are shown below.

Which electron configuration represents the element with the largest first ionisation energy?

  • 1s22s22p63s2

  • 1s22s22p63s23p4

  • 1s22s22p63s23p6

  • 1s22s22p63s23p64s2

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101 mark

How are the elements ordered in the periodic table?

  • By atomic number

  • According to relative atomic mass 

  • By reactivity

  • In order of electronegativity

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