Question

The electronic configuration of a dipositive metal is 2, 8, 14 and its atomic mass is 56 amu. The number of neutrons in its nuclei would be:

• A. 30
• B. 32
• C. 34
• D. 42

Answer 1

The correct option is A 30

Dipositive ions mean an ion formed by the loss of two electrons.

Total number of electrons in dispositive ion $=2+8+14=24$

Therefore, the total number of electrons in an atom $=$ Number of electrons in ionic state $+$ number of electrons losses

The atomic number of the metal (Z) $=24+2=26$
number of neutrons $=A–Z$

$A=$ Mass number

$Z=$ Atomic number
number of neutrons $=56–26=30$