222 Rn 86
urgent |
The general representation of an element is
AZX
where X is the symbol of the element, Z is its atomic number and A is its mass number. We are given that for radon, the atomic number is 86 and the mass number is 222. In a neutral atom
atomic number = number of protons = number of electrons
Thus, in radon, the number of protons and electrons is 86. Since
mass number = number of protons + number of neutrons
therefore, if 222 is the mass number, then number of neutrons = mass number - number of protons
= 222 - 86
= 136