Kation adalah muatan positif, yang terbentuk saat atom/molekul kekurangan elektron. Jika atom X melepaskan 1 elektron, akan membentuk ion positif \(\ce{X+}\). Jika atom X melepaskan 2 elektron, akan membentuk ion positif \(\ce{X^{2+}}\). Dan seterusnya.
Berikut adalah beberapa contoh kation:
KATION
| Unsur | Kation | Nama | |
| Golongan IA | \(\ce{Li}\) | \(\ce{Li+}\) | Litium |
| \(\ce{Na}\) | \(\ce{Na+}\) | Natrium | |
| \(\ce{K}\) | \(\ce{K+}\) | Kalium (potasium) | |
| \(\ce{Rb}\) | \(\ce{Rb+}\) | Rubium | |
| \(\ce{Cs}\) | \(\ce{Cs+}\) | Cesium | |
| Golongan IIA | \(\ce{Mg}\) | \(\ce{Mg^{2+}}\) | Magnesium |
| \(\ce{Ca}\) | \(\ce{Ca^{2+}}\) | Kalsium | |
| \(\ce{Sr}\) | \(\ce{Sr^{2+}}\) | Stronsium | |
| \(\ce{Ba}\) | \(\ce{Ba^{2+}}\) | Barium | |
| Golongan IIIA | \(\ce{Al}\) | \(\ce{Al^{3+}}\) | Alumunium |
| \(\ce{Ga}\) | \(\ce{Ga^{3+}}\) | Galium | |
| \(\ce{In}\) | \(\ce{In^{3+}}\) | Indium | |
| \(\ce{Tl}\) | \(\ce{Tl^{3+}}\) | Talium | |
| Golongan IVA | \(\ce{Sn}\) | \(\ce{Sn^{2+}}\) | Timah (II) |
| \(\ce{Sn}\) | \(\ce{Sn^{4+}}\) | Timah (IV) | |
| \(\ce{Pb}\) | \(\ce{Pb^{2+}}\) | Timbal (II) | |
| \(\ce{Pb}\) | \(\ce{Pb^{4+}}\) | Timbal (IV) | |
| Golongan B | \(\ce{Ag}\) | \(\ce{Ag+}\) | Perak |
| \(\ce{Ni}\) | \(\ce{Ni^{2+}}\) | Nikel | |
| \(\ce{Cd}\) | \(\ce{Cd^{2+}}\) | Cadmium | |
| \(\ce{Zn}\) | \(\ce{Zn^{2+}}\) | Seng | |
| \(\ce{Cr}\) | \(\ce{Cr^{3+}}\) | Kromium | |
| \(\ce{Pt}\) | \(\ce{Pt^{4+}}\) | Platina | |
| \(\ce{Cu}\) | \(\ce{Cu^{+}}\) | Tembaga (I) | |
| \(\ce{Cu^{2+}}\) | Tembaga (II) | ||
| \(\ce{Hg}\) | \(\ce{Hg^{+}}\) | Raksa (I) | |
| \(\ce{Hg^{2+}}\) | Raksa (II) | ||
| \(\ce{Au}\) | \(\ce{Au^{+}}\) | Emas (I) | |
| \(\ce{Au^{3+}}\) | Emas (III) | ||
| \(\ce{Fe}\) | \(\ce{Fe^{2+}}\) | Besi (II) | |
| \(\ce{Fe^{3+}}\) | Besi (III) | ||
| \(\ce{Co}\) | \(\ce{Co^{2+}}\) | Kobalt (II) | |
| \(\ce{Co^{3+}}\) | Kobalt (III) | ||
| Kation lainnya | \(\ce{NH4+}\) | Amonium |