Atoms Elements and Compounds Practice Questions
IGCSE (Cambridge) · IGCSE Chemistry · 145 free MCQs with instant results and detailed explanations.
145
Total
41
Easy
71
Medium
33
Hard
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Sample Questions from Atoms Elements and Compounds
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Q1
Easy
What is the smallest particle of an element that retains the properties of that element?
A.
Atom
B.
Molecule
C.
Compound
D.
Ion
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Correct Answer: A
An atom is the basic unit of an element and retains all its properties. Molecules are made of two or more atoms bonded together, while compounds consist of different elements. Ions are charged atoms or molecules.
Q2
Easy
Which of the following represents a compound?
A.
O2
B.
NaCl
C.
He
D.
N2
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Correct Answer: B
Sodium chloride (NaCl) is a compound formed from sodium and chlorine atoms. In contrast, O2 (oxygen) and N2 (nitrogen) are diatomic molecules, while He is a noble gas and not a compound.
Q3
Easy
What is the main difference between an element and a compound?
A.
Elements can be broken down into simpler substances.
B.
Compounds are made of two or more different types of atoms.
C.
Elements are always liquid at room temperature.
D.
Compounds cannot exist in nature.
Show Answer & Explanation
Correct Answer: B
Compounds are substances formed when two or more different types of atoms bond together, while elements consist of only one type of atom. This is the key distinction.
Q4
Medium
Which of the following statements correctly describes an atom?
A.
An atom is the smallest unit of an element that retains its chemical properties.
B.
An atom can be subdivided into protons, neutrons, and electrons.
C.
An atom is made up of only one type of particle.
D.
An atom consists of a nucleus only, without any surrounding electrons.
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Correct Answer: A
An atom is defined as the smallest unit of an element that maintains the chemical properties of that element, which is why option A is correct.
Q5
Medium
If the atomic number of an element is 12, how many electrons does a neutral atom of this element have?
A.
6
B.
12
C.
24
D.
0
Show Answer & Explanation
Correct Answer: B
In a neutral atom, the number of electrons is equal to the atomic number. Therefore, if the atomic number is 12, the atom has 12 electrons.
Q6
Medium
Which of the following represents a compound?
A.
O2
B.
H2O
C.
Na
D.
Ar
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Correct Answer: B
A compound is formed when two or more different elements chemically bond. H2O is a compound made of hydrogen and oxygen, while the others are either single elements or diatomic molecules.
Q7
Medium
Which of the following elements has similar chemical properties to chlorine?
A.
Fluorine
B.
Sodium
C.
Calcium
D.
Bromine
Show Answer & Explanation
Correct Answer: D
Chlorine and bromine are both halogens, which means they are in the same group of the periodic table and exhibit similar chemical properties, making option D correct.
Q8
Hard
What is the maximum number of electrons that can be accommodated in the third shell of an atom?
A.
8
B.
18
C.
32
D.
2
Show Answer & Explanation
Correct Answer: B
The third shell can hold a maximum of 18 electrons according to the 2nĀ² rule, where n is the shell number. For n=3, 2(3)Ā² = 18.
Q9
Hard
Which of the following compounds contains both ionic and covalent bonds?
A.
NaCl
B.
NH4Cl
C.
MgO
D.
CO2
Show Answer & Explanation
Correct Answer: B
NH4Cl contains the ammonium ion (NH4+), which is covalently bonded, and chloride ion (Cl-), which forms an ionic bond with NH4+. This makes NH4Cl a compound with both types of bonding.
Q10
Hard
Which of the following correctly describes the atomic theory proposed by Dalton?
A.
Atoms are indivisible particles that combine in simple whole-number ratios.
B.
Atoms can be created and destroyed during chemical reactions.
C.
All atoms of different elements have identical properties.
D.
Atoms are composed of protons, neutrons, and electrons.
Show Answer & Explanation
Correct Answer: A
Dalton's atomic theory states that atoms are indivisible and combine in simple ratios to form compounds. Options B and C are incorrect, as atoms cannot be created or destroyed in reactions, and atoms of different elements are not identical. Option D, while true, is not a part of Dalton's original theory.
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Atoms Elements and Compounds ā IGCSE (Cambridge) IGCSE Chemistry Practice Questions Online
This page contains 145 practice MCQs for the chapter Atoms Elements and Compounds in IGCSE (Cambridge) IGCSE Chemistry. The questions are organized by difficulty ā 41 easy, 71 medium, 33 hard ā so you can choose the right level for your preparation.
Every question includes a detailed explanation to help you understand the concept, not just memorize answers. Take a timed quiz to simulate exam conditions, or practice at your own pace with no time limit.