Question

14. If the mass number of an element is 40 and its atomic number is 20. Calculate the number of
neutrons and protons respectively. *
(1 Point)
(a) 20:20
(b) 18:20
O (C) 20:18
• (d) 18:18

Answer 1

Answer is (A)

20:20

Explanation:

mass of an electron is no. of neutrons + no. of protons

And number of protons = atomic number of element .

So element contains 20 protons .

And also neutrons + protons = 40 .

neutrons = 40-20

Neutrons = 20