Post Utme Chemistry Past Questions and Answers

Question 1171:

An element which exists in more than one crystalline form is said to exhibit.

A. Polymorphism
B. Isotopy
C. Allotropy
D. Isomerism

Question 1172:

Which of the following is an example of a chemical change?

A. Freezing of water
B. Dissolution of \(NaCl\) in water
C. Rusting of iron
D. Separating a liquid mixture by distillation

Question 1173:

The electronic configuration in the ground state of the chloride ion \(\left( Cl ^{-}\right)\)is

A. \(1 s ^{2} 2 s ^{2} 2 p ^{6} 3 s ^{2} 3 p ^{5}\)
B. \(1 s ^{2} 2 s ^{2} 2 p ^{6} 3 s ^{2} 3 p ^{6}\)
C. \(1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{7}\)
D. \(1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 d^{8}\)

Question 1174:

The oxidation number of oxygen in \(BaO _{2}\)

A. \(-2\)
B. \(-4\)
C. \(-1\)
D. O

Question 1175:

Which ONE of the following statements is true for the \(p\) - block elements?

A. Electronegativity increases as we go down a group
B. Electronegativity increases regularly from left to right across a period
C. Electronegativity decreases regularly from left to right across a period
D. Electronegativity remains almost constant across a period