Cambridge O Level Chemistry · Syllabus 5070 · Atoms, Elements and Compounds
Cation
What is Cation?
A positively charged ion, formed when an atom loses one or more electrons. Metal atoms commonly form cations by losing their outer-shell electrons. The nucleus is unchanged, so the proton number and therefore the element stay the same; the positive charge arises simply because there are now more protons than electrons.
This definition is part of the Atoms, Elements and Compounds chapter in Cambridge O Level Chemistry.
Questions students ask about Cation
How does an ionic bond form?
An ionic bond forms in two separate steps. First, outer electrons are transferred from a metal atom to a non-metal atom: the metal atom loses electrons to become a positive ion (a cation) and the non-metal atom gains them to become a negative ion (an anion). Second, the oppositely charged ions attract one another. The ionic bond is that strong electrostatic attraction between oppositely charged ions, not the transfer itself. Only electrons move; the nucleus and the proton number are untouched.