Page 6 - Q & A STPM 2022 Chemistry

Chapter

1 Atoms, Molecules and

Stoichiometry

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1.1 Fundamental Particles of an Atom

Section A Multiple-choice Questions
Question 1 Term

A beam of protons, electrons and neutrons is passed between two electrically
charged plates. 1
+ + + + + +
X
Proton,
electron, Y
neutron Z
– – – – – –
Which of the following statements is not true?
A X has a lower mass than Z.
B Y is electrically neutral.
C X and Z have opposite charges.
D Y is larger in size than Z.

Answer: D
Based on the deflection, X is an electron (negatively charged), Y is a neutron
and Z is a proton (positively charged).
The size of a neutron and proton are similar.

Question 2

An atom X forms an ion with a charge of –2. Which of the following statements
is not correct if this ion has 18 electrons and 19 neutrons?
A X is an isotope of sulphur.
B X is found in Group 16 in the periodic table.
C X has a nucleon number of 35.
D X has high melting and boiling points.

Answer: D
Exam Tips
Exam Tips
Determine the number of subatomic particles in an atom of X.

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01 STPM Q&A Chem T1 layout.indd 1 4/19/19 9:28 AM