Question

An atom of tungsten (W) has 74 protons. The atomic mass of tungsten is 183.84. How many neutrons does an atom of tungsten have? Round your answer to the nearest whole number.

Answer 1

The number of neutrons in the nucleus of Tungsten is 110.

Nucleus of all atoms are composed of protons and neutrons. The atom contains electrons equal in number to the protons present inside the nucleus.The entire mass of the atom is contained in the nucleus. The total mass of the electrons is negligible when compared to the total mass of the protons and the neutrons.

Protons have an atomic mass mp of 1.007277 u, while that of neutrons mn is 1.008665 u and of me electron is 0.0005486 u.

Tungsten has 74 protons and 74 electrons.

Calculate the total mass m of 72 protons and 72 electrons.

$m= 72 ( m_p +m_e )\\=(72)(1.007277 u+0.0005486 u)\\  = 72.5634 u  $

Calculate the total mass of the neutrons by subtracting the mass m from the total mass of the nucleus M.

$M_n = M - m\\  = (183.84 u)-(72.5634 u)\\ = 111.2766u$

Divide the total mass of the neutrons by the mass of one neutron to obtain the number of neutrons.

$n =\frac{M_n}{m_n}\\  =\frac{111.2766u}{1.008665u}  \\ =110.3$

Thus the number of neutrons in Tungsten atom, rounded to the nearest whole number is 110.

 

Answer 2

The number  of neutrons  does  an atom  of tungsten (W) has  is  

110  neutrons

Explanation

Atomic mass   of tungsten =  total number of  protons  and    neutrons   in  a  nucleus  of  tungsten.

Therefore   the neutrons  of tungsten  =  Atomic mass  of tungsten- protons  of  tungsten

Atomic mass of tungsten = 183.84

Tungsten protons = 74  

Tungsten  neutron   is  therefore=   183.84 - 74  = 109.84  which is approximate

110 neutrons