Waec Chemistry Past Questions For Year 1999
Question 1
Which of the following atoms contains the highest number of electrons in the outermost shell?
- A. 8O
- B. 10Ne
- C. 15P
- D. 19K
Question 2
Calcium atom ionizes by
- A. gaining two electrons
- B. losing two electrons
- C. sharing two electrons
- D. gaining two protons
Question 3
Two radioactive elements Q and S have half-life periods of 10 hours and 20 hours respectively. Therefore
- A. S decays faster than Q
- B. Q is twice as stable as S
- C. Q emits fewer particles than S
- D. S is more stable than Q
Question 4
Which of the orbitals 4s, 4p, 4d and 4f has the lowest energy?
- A. 4f
- B. 4p
- C. 4d
- D. 4s
Question 5
Pauli Exclusion Principle is related to
- A. quantum numbers of electrons
- B. reversiblility of equlibrium reactions
- C. electronegativity values of elements
- D. collision theory of reaction rates
