Periodicity Practice Questions
IB (International Baccalaureate) · IB Chemistry HL · 130 free MCQs with instant results and detailed explanations.
130
Total
30
Easy
69
Medium
31
Hard
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Sample Questions from Periodicity
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Q1
Easy
Which of the following is a characteristic trend observed in the periodic table as you move from left to right across a period?
A.
Atomic size increases
B.
Ionization energy decreases
C.
Electronegativity increases
D.
Metallic character increases
Show Answer & Explanation
Correct Answer: C
As you move from left to right across a period, the electronegativity of the elements generally increases due to the increased nuclear charge, which enhances the ability of an atom to attract electrons.
Q2
Easy
What is the reason for the decrease in atomic radius as you move across a period from left to right?
A.
Increase in electron shielding
B.
Increase in nuclear charge
C.
Decrease in the number of protons
D.
Increase in the number of electron shells
Show Answer & Explanation
Correct Answer: B
The atomic radius decreases across a period due to the increase in nuclear charge. As protons are added to the nucleus, the positive charge pulls the electrons closer, reducing the atomic size.
Q3
Easy
Which element would you expect to have the highest ionization energy in Period 3 of the periodic table?
A.
Sodium (Na)
B.
Magnesium (Mg)
C.
Aluminum (Al)
D.
Sulfur (S)
Show Answer & Explanation
Correct Answer: D
Ionization energy tends to increase across a period. In Period 3, sulfur has a higher ionization energy compared to sodium, magnesium, and aluminum due to its increased effective nuclear charge and electron configuration.
Q4
Medium
Which of the following elements has the highest first ionization energy in Period 3 of the periodic table?
A.
Sodium (Na)
B.
Magnesium (Mg)
C.
Aluminium (Al)
D.
Chlorine (Cl)
Show Answer & Explanation
Correct Answer: D
Chlorine has the highest first ionization energy in Period 3 because it has a higher nuclear charge and a smaller atomic radius compared to the other elements listed, leading to stronger attraction between the nucleus and the outer electrons.
Q5
Medium
What trend in atomic radius is observed as you move down Group 1 in the periodic table?
A.
Atomic radius decreases
B.
Atomic radius increases
C.
Atomic radius remains constant
D.
Atomic radius fluctuates
Show Answer & Explanation
Correct Answer: B
As you move down Group 1, each successive element has an additional electron shell, which increases the distance between the outermost electrons and the nucleus, resulting in a larger atomic radius.
Q6
Medium
Which of the following elements would have the most metallic character?
A.
Silicon (Si)
B.
Phosphorus (P)
C.
Sulfur (S)
D.
Aluminum (Al)
Show Answer & Explanation
Correct Answer: D
Aluminum exhibits the most metallic character because it is situated further down and to the left in the periodic table, where metallic characteristics increase due to lower ionization energies and greater ability to lose electrons.
Q7
Medium
What is the primary reason for the increase in electronegativity across a period from left to right?
A.
Increase in atomic size
B.
Decrease in atomic mass
C.
Increase in nuclear charge
D.
Increase in shielding effect
Show Answer & Explanation
Correct Answer: C
Electronegativity increases across a period due to the increase in nuclear charge, which attracts the bonding electrons more strongly without a significant increase in shielding.
Q8
Hard
Which of the following trends is observed in the atomic radius as you move across a period from left to right in the periodic table?
A.
The atomic radius increases due to increased electron shielding.
B.
The atomic radius decreases due to increased nuclear charge.
C.
The atomic radius remains constant due to fixed electron shells.
D.
The atomic radius decreases due to decreased electron-electron repulsion.
Show Answer & Explanation
Correct Answer: B
As you move across a period, the number of protons in the nucleus increases, leading to a greater nuclear charge. This pulls the electron cloud closer to the nucleus, resulting in a decrease in atomic radius.
Q9
Hard
Which element has the highest electronegativity among the following? Consider the trends in electronegativity in the periodic table.
A.
Fluorine (F)
B.
Oxygen (O)
C.
Nitrogen (N)
D.
Chlorine (Cl)
Show Answer & Explanation
Correct Answer: A
Fluorine has the highest electronegativity of all elements according to the Pauling scale. As you move up and to the right in the periodic table, electronegativity increases, making fluorine the most electronegative element.
Q10
Hard
Which of the following statements best explains the trend in ionization energy across a period in the periodic table?
A.
Ionization energy decreases due to increased nuclear charge.
B.
Ionization energy increases due to increased nuclear charge and decreased atomic radius.
C.
Ionization energy remains constant as atomic size does not change.
D.
Ionization energy increases due to increased shielding from inner electrons.
Show Answer & Explanation
Correct Answer: B
As you move across a period from left to right, the nuclear charge increases (more protons), which pulls the electrons closer to the nucleus, thereby decreasing atomic radius and increasing ionization energy.
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Periodicity — IB (International Baccalaureate) IB Chemistry HL Practice Questions Online
This page contains 130 practice MCQs for the chapter Periodicity in IB (International Baccalaureate) IB Chemistry HL. The questions are organized by difficulty — 30 easy, 69 medium, 31 hard — 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.