Basics of Nuclear Chemistry

As we know, every atom consist of two parts; first is the inner core (nucleus) and second is the external body (revolving electrons). The external part has nearly negligible mass and the whole mass of an atom (nearly 99.9%) comes from nucleus.
Now nucleus consist of Proton and Neutron. The number of proton in a nucleus of atom is denoted by the letter Z and the number of the neutron in the nucleus of atom is denoted by the letter N.
Z is known as atomic number and Z+N is known as mass number. Note that mass number is different from atomic mass. We will discuss this in our later posts.
An atom is known by its atomic number means by the number of proton in the nucleus. If there are different number of neutron in the nucleus but have the same number of proton so such atoms are known as isotopes of the same atom.
Note that as I have said that the whole mass of atom is concentrated in the nucleus so the removal of electron will not much affect the mass of an atom, I am telling this because I will use this concept in my later post. But remember the removal of proton and neutron decreases the mass of an atom.