Revision Questions and Answers for structure and bonding

Revision Questions and Answers

1. Which ion has the most shells that contain electrons?

a. Al³⁺b. Be²⁺

c. N^3-

d. S^2-

2. Which substance contains covalent bonds but also conducts electricity?

a. brass

b. graphite

c. iodine

d. steel

3. Which electron arrangement is that of a metallic element?

a. 2, 1

b. 2, 4

c. 2, 5

d. 2, 7

4. Which molecules have the same number of protons?

a. O₂ and N₂

b. Cl₂ and Br₂c. CO₂ and SO₂

d. CH₄ and NH₃

5. Metals have positive ions in a 'sea of electrons'. Which metal atom provides most electrons for the sea?

a. aluminium

b. magnesium

c. sodium

d. zinc

6. Which substance does not have a macromolecular structure?

a. diamond

b. graphite

c. silicon dioxide

d. sodium chloride

7. Which atom has the same electronic configuration as the strontium ion?

a. calcium

b. krypton

c. rubidium

d. selenium

8. Element X has an electronic structure 2.8.8.1.
Element Y has an electronic structure 2.8.6.
What is made when X and Y react?

Type of compound         Formula

a.           covalent                     X₂Y

b.           covalent                     XY₂

c.           ionic                          X₂Y

d.           ionic                          XY₂

9. What is the formula of uranium(VI) oxide?

a. U₆O

b. U₂O₃

c. UO₃

d. UO₆

10. Graphite is used to make

a. glass

b. cutting tools

c. electrical wiring

d. electrodes

11. Which compound has both ionic and covalent bonds?

a. ammonium chloride

b. carbon dioxide

c. ethy ethanoate

d. sodium chloride

12. Elements X and Y react to form an ionic compound of formula XY. What could be the proton (atomic) numbers of X and Y?

	X	Y
a	3	8
b	6	8
c	8	16
d	12	16

13. An atom of an element contains 17 protons, 18 neutrons and 17 electrons. What is the atomic structure of another isotope of this element?

	protons	neutrons	electrons
a	17	20	17
b	17	18	16
c	18	18	17
d	20	18	17

14. Which of the following has the highest electrical conductivity?

a. aqueous sugar solution

b. solid graphite

c. solid sodium chloride

d. gaseous carbon dioxide

15. Which of the following ions has the same number of electrons as a krypton atom, atomic number 36?

a. chlorine

b. rubidium

c. sodium

d. xenon

16. Which of the following is a compound?

a. air

b. carbon

c. oxygen

d. steam

17. In which set do the three particles each have the same total number of electrons?

a	Cl-	Br-	I-
b	F-	Ne	Na+
c	K+	Ca2+	Br-
d	Li+	Na+	K+

18. An ion X⁺ has 23 nucleons and 10 electrons. What does the nucleus of the ion X⁺ contain?

	protons	neutrons
a	12	11
b	11	12
c	10	13
d	9	14

19. The table shows information about particles X and Y.

	number of protons	number of neutrons	electronic structure
X	9	10	2, 8
Y	17	20	2, 8, 8

Which statement is correct for both X and Y?

a. they are atoms of metals

b. they are atoms of noble gases

c. they are isotopes of the same element

d. they are negative ions

20. Which substance could be sodium chloride?

substance	melting point/oC	conduction of electricity when liquid	conduction of electricity when in aqueous solution
a	-114	none	none
b	-114	none	good
c	180	none	insoluble
d	808	good	good

21. Chemical bonding involves the rearrangement of 

a. molecules

b. atoms

c. electrons

d. ions

22. Solid carbon dioxide (dry ice) is used as a refrigerating agent because it readily changes directly from the solid state into the gaseous state at a low temperature. Based on the above information, what is the main intermolecular bonding in CO₂ (s) likely to be?

a. covalent bonding

b. ionic bonding

c. hydrogen bonding

d. Van der Waals forces

23. Which of the following does not contain covalent bonds?

a. graphite

b. gold

c. ice

d. diamond

24. Which atom has the same electronic configuration as the strontium ion?

a. calcium

b. krypton

c. rubidium

d. selenium

25. How does a magnesium atom form a bond with an oxygen atom?

a. by giving one pair of electrons to the oxygen atom

b. by sharing one pair of electrons, provided by the magnesium atom

c. by sharing two pairs of electrons, both pairs provided by the oxygen atom

d. by sharing two pairs of electrons, each atom donating one pair of electrons

26. In which of the following pairs do the elements form a compound by sharing electrons?

a. carbon and chlorine

b. lithium and iodine

c. neon and oxygen

d. potassium and bromine

27. Which substance does not have a macromolecular structure?

a. diamond

b. graphite

c. silicon dioxide

d. sodium chloride

28. Which substance has the highest melting point?

a. diamond

b. lead(II) bromide

c. methane

d. water

29. Substance X has a melting point higher than 500ºC. It is insoluble both in water and in organic solvents. It conducts electricity both when solid and when molten. What could X be?

a. copper

b. magnesium oxide

c. poly(ethene)

d. silica

30. Which of the following describes the structure of diamond?

a. a giant structure of atoms bonded covalently

b. a regular arrangement of oppositely charged ions

c. layers of rings of atoms

d. positively charged ions surrounded by a sea of electrons

MCQ Answers

1. d

2. b

3. a

4. d

5. a

6. d

7. b

8. c

9. c

10. d

11. a

12. d

13. a (isotopes of the same element have same number of protons but different number of neutrons)

14. b

15. b

16. d

17. b

18. b

19. d

20. d

21. c

22. d

23. b

24. b (both strontium ion and krypton have 36 electrons)

25. a (magnesium and oxygen undergo ionic bonding)

26. a

27. d (sodium chloride has a giant ionic structure made up of a lattice of positive and negative ions held tightly together by strong electrostatic forces of attraction - ionic bonds)

28. a (a lot of energy is needed to break the extremely strong C-C covalent bonds in diamond)

29. a

30. a

Structured Question Worked Solutions

1. Uranium-235 and uranium-238 are two isotopes of uranium. The table below shows the numbers of the particles in one atom of uranium-235

particle	Number
electron	92
neutron	143
proton	92

a. suggest a reason why this is known as uranium-235

b. In the table below, give the numbers of particles found in an atom of uranium-238

particle	number
electron
neutron
proton

c. Uranium-235 is radioactive and is used in the manufacture of nuclear weapons. Give one other use of uranium-235

Solutions

a. mass number = 143 + 92 = 235

b. 

particle	number
electron	92
neutron	146
proton	92

c. as a nuclear fuel in the production of nuclear energy

2. Fluorine can form either covalent or ionic bonds.
a. Draw a dot-and-cross diagram to show the bonding in
i. sodium fluoride, NaF
ii. fluorine, F₂
Your diagrams must show all electrons.

b. Explain why sodium fluoride has a higher melting point than fluorine

Solutions

ai. 

aii.

b. In NaF, the ionic bonds are very strong. In F_2, the forces of attraction between F₂ molecules are very weak. A lot of energy is required to break the strong ionic bonds. Hence, NaF has a higher melting point than F_2.
3. Use the information in the table below to answer the following questions

substance	conducts electricity when solid	melting point/oC	dissolves in water
sodium chloride	no	808	yes
sulphur	no	113	no
tungsten	yes	3377	no
wax	no	35-50	no
aluminium	yes	660	no

ai. Name two metals from the table
aii. How can you tell from the table that the substances you have chosen in (i) are metals?

b. How can you tell from the table that wax is a mixture?

ci. Name a compound from the table
cii. Explain the meaning of the word compound

d. Describe how the arrangement and movement of particles in aluminium change as the temperature rises from 659^oC to 661^oC

e. Suggest how you could separate a mixture of sulphur and sodium chloride to produce a sample of each

Solution

ai. tungsten and aluminium

aii. They conduct electricity when solid

b. Wax melts over a range of temperatures

ci. sodium chloride

cii. a compound contains 2 or more elements chemically bonded together. The ratio of each element is fixed.

d. At 659^oC, the particles are vibrating vigorously about their fixed positions. At 660^oC, Al starts to melt and the particles break free from each other and begin to move about in aggregates.

e. Dissolve the mixture in water and filter. Sulphur remains as residue while NaCl is collected as filtrate. NaCl can then be obtained by crystallization.

4. The table shows the atomic structure of six particles, represented by the letters L to Q. The particles are atoms or ions. The letters are not the symbols of the elements.

particle	electrons	protons	neutrons
L	6	6	6
M	2	2	2
N	12	12	12
O	10	12	12
P	6	6	8
Q	10	13	14

Use the letters L to Q to answer the following questions.

a. Which 2 particles are ions?

b. Which particle is a atom of a noble gas?

c. Which 2 particles are an atom and an ion of the same element?

d. Which 2 particles are isotopes of the same element?

e. Which particle has the highest atomic mass?

Solutions

a. O and Q (because O is an ion with a 2+ charge while Q is an ion with a 3+ charge)

b. M 

c. N and O (N and O have the same number of protons but different number of electrons

d. L and P have the same number of protons but different number of neutrons

e. Q. (13 + 14 =27)

5. Sodium is stored under oil because it rapidly oxidises to form sodium oxide, Na₂O.Draw a dot-and-cross diagram to show the bonding in sodium oxide. (Only need to show outer shell electrons)

Solution