If an atom, or atoms, has a balanced variety of electrons (negative charge) and protons (positive charge) they room neutral overall. However, if they space not balanced, they will be charged. These charged species are referred to as ions.

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What is a cation?

A cation has much more protons than electrons, consequently offering it a net confident charge. Because that a cation to form, one or an ext electrons have to be lost, commonly pulled far by atoms v a stronger affinity for them. The variety of electrons lost, and so the fee of the ion, is suggested after the chemical symbol, e.g. Silver (Ag) loser one electron to come to be Ag+, whilst zinc (Zn) loses two electrons to become Zn2+.



What is an anion?

An anion has more electrons than protons, consequently offering it a net an adverse charge. For an anion to form, one or more electrons need to be gained, commonly pulled far from various other atoms v a weaker affinity because that them. The variety of electrons gained, and so the fee of the ion, is suggested after the chemistry symbol, e.g. Chlorine (Cl) gains one electron to become Cl-, whilst oxygen (O) gains 2 electrons to end up being O2-.


Cation vs anion chart

The main differences between cations and also anions space summarized in the table below.






Electrode attracted to

Cathode (negative)

Anode (positive)

Formed by

Metal atoms

Non-metal atoms


Sodium (Na+), iron (Fe2+), Ammonium (NH4+)

Chloride (Cl-), Bromide (Br-), Sulfate (SO42-)

Metallic atoms organize some of your electrons relatively loosely. Consequently, they have tendency to shed electrons and type cations. Conversely, most nonmetallic atoms tempt electrons more strongly than metallic atoms, and so acquire electrons to type anions. Therefore, as soon as atoms from a metallic and also a nonmetallic aspect combine, the nonmetallic atoms often tend to attract one or more electrons far from the metallic atoms to form ions. These oppositely charged ions then attract one various other to type ionic bonds and also produce ionic compounds v no overall net charge. Examples incorporate calcium chloride (CaCl2), potassium iodide (KI) and magnesium oxide (MgO).

Cation vs anion periodic table

It have the right to be feasible to predict whether an atom will type a cation or one anion based on its place on the regular table. Halogens always type anions, alkali metals and alkaline planet metals always type cations. Many other metals form cations (e.g. Iron, silver, nickel), whilst many other nonmetals typically type anions (e.g. Oxygen, carbon, sulfur). However, some aspects are qualified of developing both cations and anions given the appropriate conditions. One instance is hydrogen, which may acquire (H-) or lose (H+) an electron, forming hydride compound such as ZnH2 (where that is an anion) and also hydron compound such as H2O (where that is a cation).

Elements in team 18 of the routine table – the “noble gases”, tend not to form ions as result of the setup of your electrons which makes them usually unreactive.


Cation vs anion size

Cations and also anions come in many sizes throughout the periodic table, as seen in this video.

Utilizing ionic properties

Ionic properties deserve to be exploited through chemists for a range of purposes. Ion-exchange chromatography for instance relies ~ above the affinity the the molecules being separated for the stationary phase based upon their fee properties to allow separation.

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Ionic nature are central to the role of battery too. Batteries have actually two electrodes made of conductive material, the cathode i m sorry is the positive finish where the electrical current leaves/electrons enter, and the anode where the electrical existing enters/ electrons leave. In between the electrodes is an electrolyte fluid or gelatin that consists of charged corpuscle – ions. Together this ionic substance reacts with the electrodes it generates electrical current. In single use, dried cell batteries, zinc is generally used together the anode whilst manganese dioxide is a popular selection for the electrolyte cathode. The zinc anode likewise acts together the battery’s container in zinc-carbon batteries so together it oxidizes during use, the components can start to leak over time.