Chemistry questions and answers

Chemistry Questions and Answers

Learn more about the properties, composition, and structure of substances (elements and compounds) with these Chemistry questions and answers. This Test can be used by students preparing for Chemistry in JAMB, WAEC, NECO or Post UTME.

1,226.

The complex compound formed by the combination of two elements with a large electronegativity difference is likely to be

A.

polar covalent

B.

giant molecular

C.

covalent

D.

ionic

Correct answer is D

Ionic bonds are also formed when there is a large electronegativity difference between two atoms.

1,227.

The shape of a graphite crystal is

A.

tetrahedral

B.

pyramidal

C.

hexagonal

D.

octahedral

Correct answer is C

Graphite is a crystalline form of the element Carbon. The atoms are arranged in a hexagonal structure.

1,228.

Which of the following elements is a metalloid?

A.

Carbon

B.

Oxygen

C.

Silicon

D.

Sodium

Correct answer is C

Some examples of metalloids include boron, silicon, germanium, arsenic etc.

1,229.

Which of the following statements about a radioactive substance is/are correct? l. lt emits radiation continuously and spontaneously. ll. The emitted radiations are affected by temperature and pressure III. The radiation can penetrate opaque matter

A.

ll only

B.

l and ll only

C.

l and lll only

D.

ll and lll only

Correct answer is C

The properties of radioactive elements holds true except that radioactive decay is not dependent on external conditions except electron capture and bombarding the radioactive material with subatomic particles.

1,230.

The d-block elements are paramagnetic because they

A.

contain paired electrons which are repelled by magnetic field

B.

contain unpaired electrons in the partially filled 3d-orbital

C.

contain paired electrons which are repelled by magnetic field force

D.

have delocalized valence electrons

Correct answer is B

Paramagnetism is a characteristic possessed by an atom with an unpaired electron.