what is ionisation?what are ions?how does ionisation take place?plz explain in simple words

Ionizationis the process by which anatomor amoleculeacquires a negative or positive charge by gaining or losingelectronsto formions, often in conjunction with other chemical changes.^[1]Ionization can result from the loss of an electron after collisions with sub atomic particles, collisions with other atoms, molecules and ions, or through the interaction with light.Heterolytic bond cleavageand heterolyticsubstitution reactionscan result in the formation of ion pairs. Ionization can occur through radioactive decay by theinternal conversionprocess, in which an excited nucleus transfers its energy to one of theinner-shell electronscausing it to be ejected.