Isotopes and ions

Isotopes

• atoms that have the same number of protons and electrons, but a different number of neutrons 

• their atomic number is the same (atomic number equals the number of protons in the nucleus of the atom)

• but their mass number is different (only protons and neutrons correspond to the atomic mass, since the mass of electrons is very small)

• does not affect the chemistry of the electron 

Hydrogen 

• hydrogen is the only element where the isotopes are given specific names

Stable and unstable isotopes 

• some isotopes are stable and some are unstable 

• unstable isotopes decay over time and eventually turn into other isotopes or elements 

• unstable isotopes are considered radioactive 

• most elements that are found in nature are made up of stable isotopes

Ions

• an ion is an electrically charged atom or group of atoms (molecules)

• it forms when an atom or a molecule gains of loses electrons 

• Ions have an unequal number of protons and electrons 

• Ionization: the process of creating an ion by adding or removing electrons 

• Cations: when an atom loses electrons, positively charged ions are formed

• Anions: when an atom gains electrons, negatively charged ions are formed

Ionization energy 

• the energy required to remove an electron from an isolated gaseous atom or molecule 

• the closer an electron is to the atomic nucleus, the stronger the attraction and the higher the ionization energy