Atomic structure and bonding - Jamb Chemistry Past Questions and Answers

Question 21:

• JAMB 1981

An element X has 127 neutrons and 82 electrons.
Its atomic number is?

A. 209
B. 105
C. 45
D. 82

Question 22:

• JAMB 1981

An element X has 127 neutrons and 82 electrons.
Its atomic number is?

A. 209
B. 105
C. 45
D. 82

Question 23:

• JAMB 1981

The mass number of an atom is?

A. The number of electrons in the atom
B. The number of protons in the nucleus of the atom
C. The number of neutrons in the nucleus of the atom
D. The sum of numbers of electrons and protons inthe atom
E. The sum of numbers of proton and neutrons in the nucleus of the atom

Question 24:

• JAMB 1981

Sodium and potassium belong to the same group of the Periodic Table. This is because?

A. Both are metals
B. Both are soft and lighter than water
C. Both form cations by losing electrons
D. Both have identical electronic configuration
E. Both react with water vigorously

Question 25:

• JAMB 1981

Which of the following is the electronic configuration of sodium?
(Atomic number of Na = 11)

A. 1s² 2s²2p⁶ 3s²
B. 1s² 2s²2p⁶ 3s² 3p1s² 2s²2p⁶ 3s¹
C. 1s² 2s²2p⁶ 3s¹
D. 1s² 2s²2p⁶ 3s^°
E. 1s² 2s²2p⁶ 4s¹