Question

mass number of an element is 18 its atom has 8 electrons find the number of proton and neutron in an atom

Answer 1

Hi friend, Mass no. (A)= p+n atomic no (Z)= no of e-=no of p+ no of protons = 8 since no of electrons= no of protons, Mass no = 18 there fore 18=8+n. 18-8=n, n=10

Therefore no of neutrons = 10

Answer 2

Given,

The mass number of an element = 18

Number of electrons = 8

To find,

We have to find the number of protons and neutrons in an atom.

Solution,

The number of protons is 8 and neutrons are 10 in an atom of mass number 18.

We can simply find the number of protons and neutrons in an atom by using the formula,

Mass number = number of protons/electrons + Number of neutrons

As we know that the number of protons and number of electrons in an atom is equal, then

Number of protons = no of electrons

Number of protons in an atom = 8

Number of neutrons = mass number - Number of protons/electrons

                                    = 18 - 8

                                    = 10

Hence, there are 8 protons and 10 neutrons in an atom of mass number 18 and 8 electrons.