Question

The atomic composition of element A is as follows: number of neutrons = x, atomic mass = 12, number of electrons = 6. The atomic composition of B is as follows: number of neutrons = y, atomic mass = 28, number of electrons = number of electrons in A + 8.
The ratio of x to y is:

• A. 7:3
• B. 3:7
• C. 2:3
• D. 3:2

Answer 1

The correct option is B 3:7

Element A is carbon (Number of electrons = 6 = Atomic number)
Number of neutrons = x = 12 – 6 = 6
Element B is silicon.
Number of electrons in A + 8 = 6 + 8 = 14
Number of neutrons = y = 28 – 14 = 14

x = 6 and y = 14
The ratio of x to y is:
x:y = 6:14 = 3:7