Chemical Reactivity — Homi Bhabha Exam Chemistry MCQs with Solutions
Free Homi Bhabha Exam Chemistry Chemical Reactivity MCQs with step-by-step solutions (7 questions). Part of Periodic Classification & Chemical Bonding. Practise online on Prepizo — no login needed.
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Questions with solutions
Q1 — Chemical Reactivity · medium · theory
Noble gases are chemically unreactive because their outermost shells are:
A. empty
B. completely filled (stable octet/duplet) ✓ Correct
C. always losing electrons
D. half filled
Solution: A complete outer shell makes noble gases stable, so they rarely react.
Q2 — Chemical Reactivity · hard · theory
An atom with only 1 electron in its outermost shell is:
A. a noble gas
B. a reactive metal that easily loses that electron ✓ Correct
C. chemically inert
D. a reactive non-metal that gains electrons
Solution: Losing the single valence electron gives a stable octet, so such atoms are reactive metals (e.g. Na).
Q3 — Chemical Reactivity · hard · theory
An atom with 7 electrons in its outermost shell tends to:
A. lose 7 electrons
B. gain 1 electron and act as a reactive non-metal ✓ Correct
C. lose 1 electron
D. stay inert
Solution: Gaining one electron completes the octet, so such atoms are reactive non-metals (e.g. Cl).
Q4 — Chemical Reactivity · medium · theory
The chemical reactivity of an element is mainly decided by the number of:
A. protons in the nucleus
B. neutrons
C. shells only
D. valence electrons ✓ Correct
Solution: Valence (outer-shell) electrons determine how an atom bonds and reacts.
Q5 — Chemical Reactivity · hard · theory
As we move down Group 1 (alkali metals), the chemical reactivity:
A. becomes zero
B. increases ✓ Correct
C. remains the same
D. decreases
Solution: Down the group the valence electron is farther from the nucleus and lost more easily, so reactivity increases.
Q6 — Chemical Reactivity · medium · theory
When a metal reacts, it usually ______ electrons, and when a non-metal reacts, it usually ______ electrons:
A. gains; loses
B. shares; loses
C. loses; shares
D. loses; gains ✓ Correct
Solution: Metals tend to lose valence electrons (forming cations); non-metals tend to gain them (forming anions).
Q7 — Chemical Reactivity · hard · theory
Atoms take part in chemical reactions mainly to achieve:
A. radioactivity
B. a stable noble-gas electronic configuration ✓ Correct
C. more neutrons
D. a higher atomic mass
Solution: Atoms react to complete their outer shell and reach the stable configuration of the nearest noble gas.