If an atom, or atoms, has actually a well balanced number of electrons (negative charge) and prolots (positive charge) they are neutral all at once. However, if they are not balanced, they will be charged. These charged species are referred to as ions.

You are watching: Why do atoms of nonmetals form anions

What is a cation?

A cation has actually even more prolots than electrons, subsequently giving it a net positive charge. For a cation to create, one or even more electrons need to be shed, typically pulled ameans by atoms with a more powerful affinity for them. The number of electrons shed, and so the charge of the ion, is indicated after the chemical symbol, e.g. silver (Ag) loses one electron to end up being Ag+, whilst zinc (Zn) loses two electrons to come to be Zn2+.



What is an anion?

An anion has actually even more electrons than protons, subsequently giving it a net negative charge. For an anion to form, one or even more electrons should be got, frequently pulled ameans from other atoms with a weaker affinity for them. The number of electrons acquired, and also so the charge of the ion, is shown after the chemical symbol, e.g. chlorine (Cl) gains one electron to end up being Cl-, whilst oxygen (O) gains two electrons to come to be O2-.


Cation vs anion chart

The major distinctions between cations and anions are summarized in the table listed below.






Electrode attracted to

Cathode (negative)

Anode (positive)

Formed by

Metal atoms

Non-steel atoms


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

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

Metallic atoms hold some of their electrons reasonably loosely. Consequently, they tend to shed electrons and also develop cations. Conversely, most nonmetallic atoms tempt electrons more strongly than metallic atoms, and so obtain electrons to form anions. Therefore, when atoms from a metallic and also a nonmetallic element incorporate, the nonmetallic atoms tfinish to attract one or even more electrons away from the metallic atoms to create ions. These oppositely charged ions then attract one other to develop ionic bonds and produce ionic compounds with no in its entirety net charge. Instances incorporate calcium chloride (CaCl2), potassium iodide (KI) and magnesium oxide (MgO).

Cation vs anion regular table

It have the right to be feasible to predict whether an atom will develop a cation or an anion based on its position on the regular table. Halogens always develop anions, alkali steels and also alkaline earth steels always form cations. Most other metals develop cations (e.g. iron, silver, nickel), whilst the majority of various other nonmetals commonly form anions (e.g. oxygen, carbon, sulfur). However, some aspects are capable of developing both cations and anions given the best conditions. One instance is hydrogen, which may gain (H-) or shed (H+) an electron, developing hydride compounds such as ZnH2 (where it is an anion) and also hydron compounds such as H2O (where it is a cation).

Elements in team 18 of the routine table – the “noble gases”, tfinish not to form ions due to the setup of their electrons which makes them primarily unreenergetic.


Cation vs anion size

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

Utilizing ionic properties

Ionic properties have the right to be exploited by chemists for a variety of purposes. Ion-exadjust chromatography for example depends on the affinity of the molecules being separated for the stationary phase based on their charge properties to enable separation.

See more: Explain Why Is Fluorine More Reactive Than Iodine More Reactive?

Ionic properties are central to the feature of batteries as well. Batteries have 2 electrodes made of conductive material, the cathode which is the positive end wbelow the electrical present leaves/electrons enter, and the anode where the electric existing enters/ electrons leave. In between the electrodes is an electrolyte liquid or gel that includes charged pposts – ions. As this ionic substance reacts via the electrodes it generates electric present. In single usage, dry cell batteries, zinc is generally used as the anode whilst manganese dioxide is a well-known option for the electrolyte cathode. The zinc anode also acts as the battery’s container in zinc-carbon batteries so as it oxidizes throughout usage, the contents have the right to start to leak over time.