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Essential Chemistry for IGCSE - Structure And Bonding (Section 4)

1
Which of the following has a simple molecular structure?
Answer
(D)
Methane
2
What is the electronic structure of an atom with the electronic configuration 2,8,1?
Answer
(A)
Sodium
3
What type of bonding is present in water (H₂O)?
Answer
(C)
Covalent
4
What happens to an atom when it loses an electron?
Answer
(B)
It becomes a positive ion.
5
Which of the following statements correctly describes the forces within the structure of diamond?
Answer
(A)
Strong covalent bonds between atoms throughout the structure.
6
What is the electronic structure of an oxygen atom (atomic number 8)?
Answer
(A)
2, 6
7
Which of the following is formed when two chlorine atoms bond?
Answer
(B)
A chlorine molecule.
8
What is the shape of the water molecule?
Answer
(D)
Bent or V-shaped
9
What type of elements typically form ionic compounds?
Answer
(C)
A metal and a nonmetal.
10
Which of the following statements are true regarding the strength of intermolecular forces?
Answer
A
C
D
11
What is the primary reason that graphite is soft, and can be used as a lubricant?
Answer
(B)
Weak intermolecular forces between layers.
12
In graphite, what type of bonds hold the carbon atoms within each layer together?
Answer
(B)
Covalent bonds.
13
Which of the following is not a property of simple molecular substances?
Answer
(D)
Conduct electricity when dissolved in water
14
What is the name given to the type of bond in a water molecule (H₂O)?
Answer
(C)
Covalent bond
15
Why can graphite conduct electricity?
Answer
(C)
It has delocalised electrons.
16
What is the key difference in structure between diamond and graphite?
Answer
(C)
Diamond has each carbon atom bonded to four others, graphite has layers of carbon atoms bonded to three others.
17
What happens to the electrons in the formation of a covalent bond?
Answer
(B)
They are shared between atoms.
18
What happens when a metal atom forms an ion?
Answer
(B)
It loses electrons and becomes a positive ion.
19
What are the forces holding the atoms together in a diamond?
Answer
(B)
Strong covalent bonds
20
Which of the following are considered a type of giant covalent structure?
Answer
A
B
C
21
What is a covalent bond?
Answer
(B)
A bond formed by sharing electrons.
22
Which of the following explains why graphite is used as a lubricant?
Answer
(C)
Because of weak forces between layers.
23
What does the term 'valence' refer to?
Answer
(C)
The number of electrons in the outer shell.
24
What is meant by the term 'delocalized electrons'?
Answer
(B)
Electrons that are free to move throughout a structure
25
How many electrons are shared in a double covalent bond?
Answer
(C)
Four
26
Which of the following describes the bond between atoms in a water molecule?
Answer
(B)
Covalent
27
Which of the following is a correct statement about the properties of diamond?
Answer
(D)
It does not conduct electricity, and has a very high melting point.
28
What type of bonding is present in chlorine gas (Cl2)?
Answer
(C)
Covalent
29
What type of bonding is present in Silicon dioxide?
Answer
(C)
Covalent
30
What is the difference between diamond and graphite in terms of electrical conductivity?
Answer
(D)
Graphite conducts electricity, diamond does not.
31
What is the main reason why diamond is so hard?
Answer
(B)
Strong covalent bonds between the carbon atoms in all directions.
32
Why is graphite used in pencils?
Answer
(C)
Because the layers can easily slide over each other.
33
Which of the following bonds involves the complete transfer of electrons?
Answer
(B)
Ionic
34
Which of the following elements is most likely to form a negative ion?
Answer
(B)
Chlorine (Cl)
35
What is the formula for magnesium oxide?
Answer
(A)
MgO
36
Why does graphite conduct electricity?
Answer
(A)
It contains delocalized electrons.
37
Which of the following describes the properties of a simple molecular substance?
Answer
(C)
Weak intermolecular forces.
38
What is the charge on the ions in the ionic structure of sodium chloride?
Answer
(A)
Sodium ions are positive, chloride ions are negative.
39
What type of ion does a metal typically form?
Answer
(B)
A cation
40
Which of the following statements is true regarding simple molecular substances?
Answer
(B)
They have low melting and boiling points.
41
What is the main type of force between molecules of methane (CH4)?
Answer
(C)
Van der Waals forces
42
Which element will most readily form a negative ion?
Answer
(B)
Fluorine (F)
43
What is the chemical formula of ammonia?
Answer
(B)
NH3
44
What is the primary reason why ionic compounds conduct electricity when molten?
Answer
(A)
The ions are free to move
45
Which factor is most important in determining the melting and boiling points of a substance?
Answer
(B)
The strength of the intermolecular forces
46
What is the key difference between ionic and covalent bonding?
Answer
(B)
Ionic involves transferring electrons; covalent involves sharing electrons.
47
Which of the following best describes the formation of an ionic bond?
Answer
(B)
Transfer of electrons between a metal and a non-metal.
48
Which allotrope of carbon is used as a lubricant?
Answer
(B)
Graphite
49
Which of the following statement is correct about the solubility of covalent compounds?
Answer
(C)
Covalent compounds are typically insoluble in water and soluble in organic solvents.
50
Why does graphite have a high melting point?
Answer
(A)
Because it has a giant covalent structure.