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.

1,316.

Two elements, X and Y are in the same group on the periodic table because they both have the same

A.

number of electronic shells

B.

number of valence electrons

C.

atomic size

D.

atomic number

Correct answer is B

The members of the same group always have the same number of electrons in the outer shell (i.e number of valence electrons).

1,317.

The atomic radii of metals are usually

A.

greater than their ionic radii

B.

equal to their ionic radii

C.

less than their ionic radii

D.

less than those of non-metals in the same period

Correct answer is A

Metals give off electrons. This means that atomic radius is always greater than the ionic radius for metals.

1,318.

Which of the following ions has an electron configuration different from the other?

A.

17CI-

B.

8O2-

C.

12Mg2+

D.

13AI3+

Correct answer is A

\(_{17}\)Cl\(^-\) = 18 electrons = 2, 8, 8

\(_{12}\)Mg\(^{2+}\), \(_{8}\)O\(^{2-}\) and \(_{13}\)Al\(^{3+}\) all have 10 electrons = 2, 8.

1,319.

Which of the following electron configurations represents that of an atom in its ground state?

A.

1s 22s12p1

B.

1s22s22p63s13p1

C.

1s22s12p3

D.

1s22s22p63s0

Correct answer is D

The ground state of an electron, the energy level it normally occupies, is the state of lowest energy for that electron.

1,320.

The number of orbitals in a p-sub level of an atom is

A.

2

B.

3

C.

5

D.

6

Correct answer is B

The p- orbital has 3 subshells; P\(_x\), P\(_y\) and P\(_z\) subshells.