A Cation is a metallic element with a positive charged ion that would be attracted to the cathode in electrolysis. A cation has more protons than electrons, consequently giving it a net positive charge. For a cation to form, one or more electrons must be lost, typically pulled away by atoms with a stronger affinity for them.
Cations as found in common spirulina culture medium formulas:
Sodium 4380 mg/l
Potassium 642 mg/l
Magnesium 10mg/l
Calcium 10 mg/l
Iron 0.8 mg/l
Comparison chart
 | Anion | Cation |
|---|---|---|
| Definition | An anion is an atom or a molecule which is negatively charged, i.e. has more number of electrons than protons. | A cation is an atom or a molecule which is positively charged, i.e. has more number of protons than electrons. |
| Charge | Negative | Positive |
| Examples | (O2-), sulfide (S2-), fluoride (F-), chloride (Cl-), bromide (Br-), iodide (I-), nitride (N3-) and hydride (H-) | sodium (Na+), Iron (Fe2+), and Lead (Pb2+) |
| Etymology | The Greek word ano (up) | The Greek word kata (down) |
| Electrode attracted to during electrolysis | Anode | Cathode |
| Type of element | a nonmetal | a metal |