Questions 5: How many protons are there in the nucleus of 86Rn222? How many neutrons, how many electrons are there in the neutral atom?
The symbol 86Rn222 means;
Atomic mass number of Rn = 222 Atomic charge number = 86
Now the charge number of an atom is the number of protons in the nucleus of the atom.
Therefore, Rn has 86 protons.
Number of neutron is the difference of atomic mass number and number of protons.
Therefore, Rn has 222 – 86 = 136 neutrons.
Number of electrons and number of protons are equal in a neutral atom.
Therefore, Rn has 86 electrons.