Basics of the Periodic Table — Homi Bhabha Class 9 Chemistry MCQs with Solutions
Free Homi Bhabha Class 9 Chemistry Basics of the Periodic Table MCQs with step-by-step solutions (13 questions). Part of Periodic Classification & Chemical Bonding. Practise online on Prepizo — no login needed.
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Questions with solutions
Q1 — Basics of the Periodic Table · medium · theory
Mendeleev arranged the elements in his periodic table in order of increasing:
A. valency
B. density
C. atomic number
D. atomic mass ✓ Correct
Solution: Mendeleev's classification was based on increasing atomic mass and similarity of properties.
Q2 — Basics of the Periodic Table · hard · theory
The modern periodic table arranges elements in order of increasing:
A. atomic mass
B. atomic number ✓ Correct
C. density
D. number of neutrons
Solution: Moseley showed atomic number is the fundamental property, so the modern table is arranged by it.
Q3 — Basics of the Periodic Table · medium · theory
The horizontal rows of the periodic table are called:
A. groups
B. periods ✓ Correct
C. families
D. shells
Solution: Horizontal rows are periods; vertical columns are groups.
Q4 — Basics of the Periodic Table · medium · theory
The vertical columns of the periodic table are called:
A. periods
B. groups ✓ Correct
C. orbits
D. blocks
Solution: Vertical columns are groups; elements in a group have similar properties.
Q5 — Basics of the Periodic Table · medium · theory
The modern periodic table has ______ periods and ______ groups:
A. 18 periods and 7 groups
B. 8 periods and 8 groups
C. 7 periods and 18 groups ✓ Correct
D. 7 periods and 8 groups
Solution: There are 7 periods (rows) and 18 groups (columns) in the modern periodic table.
Q6 — Basics of the Periodic Table · hard · theory
The elements of Group 1 (except hydrogen) are called:
A. noble gases
B. alkali metals ✓ Correct
C. alkaline earth metals
D. halogens
Solution: Group 1 metals (Li, Na, K, …) are the highly reactive alkali metals.
Q7 — Basics of the Periodic Table · hard · theory
The very unreactive elements placed in Group 18 are the:
A. noble (inert) gases ✓ Correct
B. transition metals
C. alkali metals
D. halogens
Solution: Group 18 contains the noble gases (He, Ne, Ar, …) which have complete outer shells.
Q8 — Basics of the Periodic Table · medium · theory
The elements of Group 17, such as fluorine and chlorine, are called:
A. metalloids
B. noble gases
C. halogens ✓ Correct
D. alkali metals
Solution: Group 17 elements are the halogens, which are reactive non-metals.
Q9 — Basics of the Periodic Table · easy · theory
In the modern periodic table, the elements are arranged in order of increasing
A. atomic mass
B. density
C. number of neutrons
D. atomic number ✓ Correct
Solution: The modern periodic law arranges elements by increasing atomic number (the number of protons), which removed the few anomalies present in Mendeleev's mass-based order.
Q10 — Basics of the Periodic Table · easy · theory
The horizontal rows of the periodic table are known as periods, while the vertical columns are known as
A. blocks
B. series
C. groups ✓ Correct
D. shells
Solution: The vertical columns are called groups (there are 18 of them), and the horizontal rows are called periods.
Q11 — Basics of the Periodic Table · medium · theory
Lithium, sodium and potassium all belong to Group 1 and show very similar chemical behaviour. The main reason is that each of their atoms has
A. the same total number of electrons
B. the same number of shells
C. the same number of valence (outermost) electrons ✓ Correct
D. the same atomic mass
Solution: Chemical properties depend mainly on valence electrons. Every Group 1 atom has 1 valence electron, so these metals react in similar ways even though their sizes and masses differ.
Q12 — Basics of the Periodic Table · medium · theory
On moving from left to right across a period, the size of the atoms generally decreases. The best explanation is that
A. the atoms lose all their valence electrons
B. the nuclear charge increases and pulls the electrons of the same shell closer ✓ Correct
C. new shells are being added one by one
D. electrons are being removed from the atoms
Solution: Across a period electrons keep entering the same outermost shell while the number of protons rises, so the greater nuclear charge pulls that shell inward and the atom becomes smaller.
Q13 — Basics of the Periodic Table · hard · numerical
An element belongs to Period 3 of the periodic table and its atom has 4 electrons in the outermost shell. What is the atomic number of this element?
A. 12
B. 18
C. 4
D. 14 ✓ Correct
Solution: A Period 3 atom fills the first two shells (2 + 8 = 10 electrons) and places the rest in the third shell. With 4 valence electrons the total is 2 + 8 + 4 = 14, so the atomic number is 14.