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Worksheets5.1-5.4 Revision
Total questions: 50
Worksheet time: 25mins
Name
Class
Date
1.
Which scientist proposed the atomic theory stating that matter is made up of indivisible particles called atoms?
a)
Antoine Lavoisier
b)
John Dalton
c)
Dmitri Mendeleev
d)
Democritus
2.
The smallest particle of matter that cannot be created or destroyed is called:
a)
Molecule
b)
Atom
c)
Compound
d)
Element
3.
Which term describes a molecule that consists of two atoms?
a)
Monatomic
b)
Diatomic
c)
Polyatomic
d)
Isotopic
4.
Which scientist organised atoms into a periodic table based on their properties and predicted undiscovered elements?
a)
Antoine Lavoisier
b)
John Newlands
c)
Dmitri Mendeleev
d)
Democritus
5.
In the periodic table, a horizontal row of elements is called a:
a)
Group
b)
Period
c)
Series
d)
Family
6.
In the periodic table, a vertical column of elements is called a:
a)
Row
b)
Group
c)
Period
d)
Set
7.
Which of the following is monatomic?
a)
Oxygen (O₂)
b)
Helium (He)
c)
Nitrogen (N₂)
d)
Hydrogen (H₂)
8.
Which is an example of a molecular compound?
a)
Helium
b)
Oxygen gas
c)
Water
d)
Iron
9.
What does the term 'pure substance' mean?
a)
Contains only one type of substance
b)
A mixture of several substances
c)
Cannot be melted
d)
Is always a solid
10.
What is the chemical symbol for oxygen?
a)
Ox
b)
O
c)
Oy
d)
Oxg
11.
Which of the following is a suspension?
a)
Saltwater
b)
Dirt mixed in water
c)
Air
d)
Sugar dissolved in water
12.
Which scientist proved that matter cannot be created or destroyed?
a)
John Dalton
b)
Antoine Lavoisier
c)
Dmitri Mendeleev
d)
John Newlands
13.
Which of these is a polymer?
a)
Carbon dioxide
b)
Polyethylene
c)
Sodium chloride
d)
Water
14.
What does a chemical formula show?
a)
Mass of the atoms
b)
Elements and number of atoms in a substance
c)
State of matter
d)
Colour of the atoms
15.
The formula H₂O indicates:
a)
One atom of oxygen and two atoms of hydrogen
b)
Two atoms of oxygen and one of hydrogen
c)
Only oxygen atoms
d)
Only hydrogen atoms
16.
Why did Mendeleev leave gaps in his periodic table?
a)
He wanted to make it symmetrical
b)
To predict undiscovered elements
c)
He ran out of known elements
d)
To group metals together
17.
Why are noble gases such as helium described as monatomic?
a)
They form molecules with two atoms
b)
They exist as single atoms
c)
They are made of compounds
d)
They contain three atoms
18.
Which feature is common to all elements in the same group of the periodic table?
a)
Same number of protons
b)
Similar chemical properties
c)
Same atomic mass
d)
Same melting point
19.
Which property makes a colloid different from a suspension?
a)
It contains only one atom type
b)
Its particles remain mixed without settling
c)
It dissolves completely in water
d)
It forms crystals
20.
Why is water considered a compound?
a)
It contains two different elements bonded together
b)
It is found naturally
c)
It is a pure substance
d)
It can be frozen
21.
Which of these is classified as a diatomic molecule?
a)
Helium
b)
Oxygen gas
c)
Neon
d)
Sodium
22.
Why are the horizontal rows in the periodic table called 'periods'?
a)
They show elements’ melting points
b)
They arrange elements by increasing atomic number
c)
They group elements with similar properties
d)
They show isotopes
23.
Which statement describes a mixture?
a)
Cannot be separated physically
b)
Made up of two or more substances combined physically
c)
Made of identical atoms
d)
Always has a fixed composition
24.
Which term describes a molecule with two hydrogen atoms and one oxygen atom?
a)
Monatomic
b)
Diatomic
c)
Compound
d)
Element
25.
Why do scientists use chemical symbols for elements?
a)
To make the names longer
b)
To identify and represent elements clearly
c)
To indicate their mass
d)
To rank them
26.
If sodium (Na) and chlorine (Cl) bond, which type of substance will they form?
a)
Molecular element
b)
Compound
c)
Mixture
d)
Suspension
27.
A student observes that nitrogen always exists as N₂ in nature. What type of molecule is this?
a)
Monatomic
b)
Diatomic
c)
Polymer
d)
Compound
28.
A scientist finds a substance that contains only carbon atoms. This substance is:
a)
A compound
b)
An element
c)
A mixture
d)
A polymer
29.
Which periodic table feature would help you quickly identify if an element is a metal or non-metal?
a)
Group numbers
b)
Position relative to the zig-zag line
c)
Colour of the symbol
d)
Atomic mass
30.
Which example best fits a solution?
a)
Sugar dissolved in water
b)
Oil and water
c)
Sand and water
d)
Smoke in air
31.
Which feature of Mendeleev’s table made it different from earlier versions?
a)
He placed metals on one side
b)
He left spaces for predicted elements
c)
He grouped elements alphabetically
d)
He arranged them by colour
32.
If a substance contains particles too small to see, that do not settle out, it is a:
a)
Suspension
b)
Colloid
c)
Solution
d)
Compound
33.
Which of the following best represents a lattice structure?
a)
Salt crystals
b)
Water molecules
c)
Oxygen gas
d)
Carbon dioxide
34.
Which chemical formula represents methane?
a)
CH₄
b)
H₂O
c)
CO₂
d)
C₂H₆
35.
Which element symbol represents nitrogen?
a)
Ni
b)
N
c)
Nt
d)
Ng
36.
Comparing Mendeleev’s table to the modern periodic table, which feature has changed the most?
a)
Grouping by similar properties
b)
Arrangement by atomic mass to atomic number
c)
Use of chemical symbols
d)
Number of metals
37.
Why might water (H₂O) be considered more useful than oxygen gas (O₂) in chemical reactions?
a)
Water has more atoms
b)
Water contains two elements, allowing more reaction types
c)
Oxygen is unstable
d)
Water is always a gas
38.
A student claims helium is a compound because it appears in the periodic table. What is the flaw in this reasoning?
a)
Helium is a pure element
b)
Helium has no electrons
c)
Helium cannot be found naturally
d)
Helium is not on the periodic table
39.
A sample is cloudy and the particles settle after a few minutes. It is most likely a:
a)
Colloid
b)
Suspension
c)
Solution
d)
Pure substance
40.
If the atomic number of an element increases, where will it appear in the periodic table?
a)
Higher up
b)
Further to the right or down
c)
On the far left
d)
It will disappear
41.
Which is an example of a pure substance that is also a compound?
a)
Gold
b)
Carbon dioxide
c)
Helium
d)
Oxygen gas
42.
Which part of Dalton’s atomic theory is still accepted today?
a)
Atoms are indivisible and indestructible
b)
Atoms can change into other types
c)
Atoms have no subatomic particles
d)
All atoms weigh the same
43.
Which comparison is correct?
a)
Compound – single type of atom
b)
Molecule – two or more atoms bonded
c)
Mixture – cannot be separated
d)
Atom – contains multiple elements
44.
Why are formulas like CO₂ important to scientists?
a)
They show the total weight of a substance
b)
They show the number and type of atoms
c)
They describe the taste of a substance
d)
They group substances by state
45.
Which of these changes is physical, not chemical?
a)
Dissolving sugar in water
b)
Burning wood
c)
Rusting iron
d)
Reacting acid with base
46.
How does a polymer differ from a simple molecule?
a)
It contains many repeating units
b)
It has fewer atoms
c)
It is always made of metals
d)
It cannot be natural
47.
Which of the following is NOT a feature of mixtures?
a)
Components can be separated physically
b)
Composition is fixed
c)
Contains two or more substances
d)
Properties vary depending on composition
48.
Why might scientists prefer the modern periodic table over Mendeleev’s original?
a)
It lists more elements and is arranged by atomic number
b)
It uses colours instead of symbols
c)
It has fewer gaps
d)
It avoids grouping similar elements
49.
Which of these best represents a diatomic molecule?
a)
H₂
b)
CO₂
c)
NaCl
d)
CH₄
50.
If a mixture of sand and water is left to stand, what will happen?
a)
Sand will dissolve
b)
Sand will settle at the bottom
c)
Nothing will change
d)
Sand will float
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