How many neutrons are in an atom of mercury?
120. The atomic mass of Mercury (Hg) is about 200. The atomic number is 80.
The atomic number of Mercury(Hg) is 80; since atomic number of an atom= No. of protons.Thus No. of protons in Mercury is 80. Also No. of protons = No. of electrons (In an neutral Atom; which is not an ion).Therefore No. of electrons is also 80. Next, Mass number(Atomic Mass) of Mercury is 160. Mass Number(Atomic Mass)= No. of Protons + No. of Neutrons. Hence calculating that we get No. of Neutrons also to be…
The element mercury (Hg) has 80 protons and 80 neutrons. It exists in several different isotopes which have different numbers of neutrons, however, the average number of neutrons in a mercury atom is 121. (The atomic weight is 200.59 which would require 80 protons and 120.59 neutrons, although of course every atom has only whole numbers of neutrons, you only get fractions because you are getting an average of different isotopes.)
From the periodic table, we have mercury's atomic number as 80 and relative atomic mass as 201. So mercury has 80 protons and 80 electrons. The exact number of neutrons a mercury atom would have depends on its isotopic form, but for the most abundant isotope mercury-202 (about 30%), it would have 202 - 80 = 122 neutrons. Else just take 201 - 80 and you will get 121 neutrons as a rough figure.