Radioactive decay
Stable nuclei
An atom's The central part of an atom. It contains protons and neutrons, and has most of the mass of the atom. The plural of nucleus is nuclei. can only be stable if it has a certain number of Uncharged subatomic particle, with a mass of 1 relative to a proton. The relative charge of a neutron is 0. for the number of Subatomic particle with a positive charge and a relative mass of 1. The relative charge of a proton is +1. it has.
Elements with fewer protons, such as the ones near the top of the A tabular representation of all known elements in order based on atomic number, eg all the noble gases are found on the right of the periodic table., are stable if they have the same number of neutrons and protons, for example carbon, carbon-12 is stable and has six protons and six neutrons.
However as the number of protons increases, more neutrons are needed to keep the nucleus stable, for example lead, lead-206 has 82 protons and has 124 neutrons.
Nuclei with too many, or too few, neutrons do exist naturally but are unstable and will The process in which unstable atomic nuclei break apart or change, releasing radiation as they do so., in a random process, emitting Energy carried by particles from a radioactive substance, or spreading out from a source..