JAMB and WAEC Chemistry questions

800 questions with answers and explanations. Tap an option to check yourself.

1. Question 141· Atomic structure and bonding· WAEC

   What is the electron configuration of an atom of atomic number 13?

   • A2, 11
   • B2, 8, 2, 1
   • C2, 3, 8
   • D2, 8, 3

   Show answer

   Explanation and discussion

2. Question 142· Atomic structure and bonding· JAMB

   The bond in sodium chloride is:

   • Acovalent
   • Bmetallic
   • Cionic
   • Dhydrogen

   Show answer

   Explanation and discussion

3. Question 143· Atomic structure and bonding· JAMB

   The configuration 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹ belongs to

   • Asodium
   • Bpotassium
   • Ccalcium
   • Dargon

   Show answer

   Explanation and discussion

4. Question 144· Atomic structure and bonding· WAEC

   The atoms ³⁵Cl and ³⁷Cl differ in their number of

   • Aneutrons
   • Belectrons
   • Cprotons
   • Dvalency electrons

   Show answer

   Explanation and discussion

5. Question 145· Atomic structure and bonding· WAEC

   The electron configuration of chlorine (atomic number 17) is

   • A2, 8, 8
   • B2, 8, 7
   • C2, 7, 8
   • D2, 8, 1

   Show answer

   Explanation and discussion

6. Question 146· Atomic structure and bonding· WAEC

   Isotopes of an element have

   • Adifferent numbers of electrons
   • Bthe same number of neutrons but different numbers of protons
   • Cdifferent atomic numbers
   • Dthe same number of protons but different numbers of neutrons

   Show answer

   Explanation and discussion

7. Question 147· Atomic structure and bonding· JAMB

   The electronic configuration of the calcium ion, Ca²⁺ (atomic number 20), is

   • A2, 8, 8, 2
   • B2, 8, 8
   • C2, 8, 10
   • D2, 8, 6

   Show answer

   Explanation and discussion

8. Question 148· Atomic structure and bonding· JAMB

   Which element has the highest electronegativity?

   • Achlorine
   • Bfluorine
   • Coxygen
   • Dsodium

   Show answer

   Explanation and discussion

9. Question 149· Atomic structure and bonding· WAEC

   The shape of a methane molecule is

   • Abent
   • Blinear
   • Ctrigonal planar
   • Dtetrahedral

   Show answer

   Explanation and discussion

10. Question 150· Atomic structure and bonding· JAMB

    Which of the following contains a dative (coordinate) covalent bond?

    • ACH₄
    • BNH₄⁺
    • CNaCl
    • DH₂

    Show answer

    Explanation and discussion

11. Question 151· Atomic structure and bonding· WAEC

    The particles found in the nucleus of an atom are

    • Aprotons and neutrons
    • Belectrons and protons
    • Celectrons only
    • Dneutrons and electrons

    Show answer

    Explanation and discussion

12. Question 152· Atomic structure and bonding· WAEC

    An atom of an element has 11 protons and 12 neutrons. Its mass number is

    • A12
    • B11
    • C23
    • D1

    Show answer

    Explanation and discussion

13. Question 153· Atomic structure and bonding· WAEC

    The element with electron configuration 2, 8, 2 belongs to

    • AGroup 2, Period 3
    • BGroup 3, Period 2
    • CGroup 2, Period 2
    • DGroup 8, Period 3

    Show answer

    Explanation and discussion

14. Question 154· Atomic structure and bonding· JAMB

    Which molecule has a tetrahedral shape?

    • ACH₄
    • BCO₂
    • CH₂O
    • DBF₃

    Show answer

    Explanation and discussion

15. Question 155· Chemical combination· WAEC

    Calculate the percentage by mass of nitrogen in ammonium trioxonitrate(V), NH₄NO₃. [N = 14, H = 1, O = 16]

    • A35%
    • B17.5%
    • C28%
    • D46.7%

    Show answer

    Explanation and discussion

16. Question 156· Chemical combination· JAMB

    What mass of oxygen combines with 4 g of hydrogen to form water? (H = 1, O = 16)

    • A8 g
    • B32 g
    • C16 g
    • D64 g

    Show answer

    Explanation and discussion

17. Question 157· Chemical combination· WAEC

    What volume does 0.25 mol of carbon(IV) oxide occupy at s.t.p.? [molar volume = 22.4 dm³]

    • A5.6 dm³
    • B89.6 dm³
    • C22.4 dm³
    • D0.011 dm³

    Show answer

    Explanation and discussion

18. Question 158· Chemical combination· JAMB

    Find the percentage by mass of nitrogen in NH₄NO₃. (N = 14, H = 1, O = 16)

    • A35%
    • B17.5%
    • C28%
    • D46.7%

    Show answer

    Explanation and discussion

19. Question 159· Chemical combination· JAMB

    In the reaction 2KClO₃ → 2KCl + 3O₂, how many moles of oxygen are produced from 2 mol of KClO₃?

    • A1.5 mol
    • B2 mol
    • C3 mol
    • D6 mol

    Show answer

    Explanation and discussion

20. Question 160· Chemical combination· JAMB

    How many molecules are in 4.4 g of carbon(IV) oxide? [C = 12, O = 16, L = 6.0 × 10²³]

    • A1.2 × 10²³
    • B6.0 × 10²³
    • C2.6 × 10²⁴
    • D6.0 × 10²²

    Show answer

    Explanation and discussion