Question

X is an element with mass number 40 and electronic configuration 2,8,8,2.
In the nucleus of X, there are;
a. 40 protons and 20 electrons
b. 20 protons and 40 neutrons
c. 20 neutrons and 20 protons
d. 20 protons and 40 electrons

Answer 1

Your answer is option C

No of neutrons = mass no - atomic no

Atomic no = number of protons

Atomic no = 20

Mass no = 40

40 - 20 = 20 neutrons

So, 2 protons and 20 neutrons

Please mark me brainliest

Answer 2

Answer:

option C is the right answer.

Explanation:

no. of electrons = 2+8+8+2= 20

no. of electrons = no. of protons

so, no. of protons = 20

mass no. = no. of protons + no. of neutrons

So,

no. of neutrons = mass no. - no. of protons

= 40 - 20

= 20 neutrons

Ans. 20 protons and 20 neutrons