⚛️ Chapter 2: Properties of Materials
Grade 8 Science Assessment
📝 Total Questions:
30
✅ Pass Mark:
70%
⏱️ Time:
45 minutes
1
What does the atomic number tell you?
The number of neutrons
The number of protons
The number of electrons only
The total mass
2
What does the mass number tell you?
The number of protons only
The number of protons and neutrons in total
The number of electrons
The number of shells
3
What charge do protons have?
Positive charge (+1)
Negative charge (-1)
No charge
Neutral charge
4
What charge do electrons have?
Positive charge (+1)
Negative charge (-1)
No charge
Variable charge
5
Lithium has an atomic number of 3 and a mass number of 7. How many neutrons does it have?
3
4
7
10
6
Which group in the Periodic Table contains the noble gases?
Group 1
Group 7
Group 8
Group 2
7
Why don't noble gases react to form compounds?
They are too heavy
Their outermost electron shell is completely full
They have no electrons
They are radioactive
8
What is Group 1 in the Periodic Table called?
Noble gases
Halogens
Alkali metals
Transition metals
9
What is Group 7 in the Periodic Table called?
Noble gases
Halogens
Alkali metals
Rare earth metals
10
When atoms are more stable, what does this mean?
They have more protons
Their outermost electron shell is completely full
They are heavier
They have no neutrons
11
What happens when sodium loses an electron?
It becomes a negative ion
It becomes a positive ion (Na⁺)
Nothing happens
It becomes a different element
12
What happens when chlorine gains an electron?
It becomes a positive ion
It becomes a negative ion (Cl⁻)
Nothing happens
It explodes
13
What is an ionic bond?
When atoms share electrons
Attraction between a positively charged ion and negatively charged ion
When atoms stick together with glue
When neutrons combine
14
What is the formula for sodium chloride?
NaCl
NaCl₂
Na₂Cl
NaC
15
What is the formula for magnesium oxide?
MgO
MgO₂
Mg₂O
MgCl₂
16
What is a covalent bond?
When atoms lose or gain electrons
When atoms share electrons
When metals bond
When atoms repel each other
17
What is the formula for hydrogen chloride?
HCl
H₂Cl
HCl₂
H₂Cl₂
18
What is the formula for a hydrogen molecule?
H
H₂
H₃
H₂O
19
What is the formula for ammonia?
NH₃
NH₂
NH₄
N₃H
20
What type of structure is sodium chloride?
Simple molecular structure
Giant ionic structure (lattice)
Giant covalent structure
Metallic structure
21
What type of structure is diamond?
Giant ionic structure
Giant covalent structure
Simple molecular structure
Polymer structure
22
How many covalent bonds does each carbon atom form in diamond?
Two
Three
Four
Five
23
Why is diamond so hard?
It is very light
It has a strong, rigid, three-dimensional structure
It contains metal atoms
It is magnetic
24
What type of structure is graphite?
Giant ionic structure
Giant covalent structure in layers
Simple molecular structure
Metallic structure
25
Why is graphite soft and slippery?
It contains water
The layers can easily slide over each other because forces between layers are weak
It has no covalent bonds
It is very small
26
What are large structures like diamond and graphite called?
Micromolecules
Macromolecules
Simple molecules
Compounds
27
Do ionic compounds have high or low melting points?
Very high melting points
Very low melting points
Medium melting points
They cannot melt
28
Do simple covalent molecules have high or low melting points?
Very high melting points
Low melting points
They don't have melting points
Same as ionic compounds
29
In Group 1 (alkali metals), which element is MOST reactive?
Lithium
Sodium
Potassium
They are all equally reactive
30
In Group 7 (halogens), which element is MOST reactive?
Fluorine
Chlorine
Bromine
They are all equally reactive
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