What is the difference between cation and anion?

Question

Vedantu Content Team · Accepted Answer

Hint: When an atom loses or gains electrons to form an ionic bond, it becomes an ion. Cations and anions are formed based on the tendency of an atom to lose an electron or to gain an electron. They are exactly opposite to each other and form the basis of ionic bonds.Complete step by step solution:-According to lewis rule, every atom tries to achieve the electronic configuration of the noble gases. This can be done either by losing or gaining electrons which form ionic bonding between the atoms or by sharing of electrons which forms covalent bonding.-When an atom combines with another atom as a result of ionic bonding, the two different species formed which have their octet complete are called the ions. Among them, one ion has an excess of electrons which is called anion and one ion has a deficiency of electrons which is called a cation.-Cation is formed when an atom loses its electrons to attain the noble gas electronic configuration to become stable. Anion is formed when an atom gains electrons to attain the noble gas electronic configuration to become stable.-Both the anion and the cation are opposite in charge and so are attracted by the electrostatic force of attraction leading to the formation of a compound. The bond that joins them is called an ionic bond. Since the force of attraction is electrostatic, the ionic bond is also referred to as an electrostatic bond.The differences between a cation and an anion can be shown in the following table-CATIONANIONIt has a positive charge on itIt has a negative charge on itThey are formed from metalsThey are formed from non-metalsThey get attracted to the negative terminal of the electric field called the cathodeThey get attracted to the positive terminal of the electric field called the anodeThey have more protons and fewer electronsThey have more electrons and fewer protonsThey are smaller in size than anions due to more force of attractionThey are larger than cations due to less force of attractionOrganic cations are called carbocationsOrganic anions are called carbanionsThey occupy the space between two anions in the crystal latticeThey usually occupy the most of the space of a crystal latticeTheir atoms have very less value of electronegativityTheir atoms have a large value of electronegativityThey have less number of valence electronsThey have more number of valence electronsEg. $N{{a}^{+}},M{{g}^{2+}},A{{l}^{3+}}$ Eg. $C{{l}^{-}},{{O}^{2-}},P{{O}_{4}}^{3-}$ Note: Not all the compounds exist in nature that is stable only when they attain noble gas configuration. There are certain hypovalent, hypervalent and odd electron species which are stable without having their octet complete. They do not end up making their cations and anions to reach stability. Eg. $PC{{l}_{5}},S{{F}_{6}},SnC{{l}_{2}},Ge{{H}_{3}},NO,Cl{{O}_{2}}$

CATION	ANION
It has a positive charge on it	It has a negative charge on it
They are formed from metals	They are formed from non-metals
They get attracted to the negative terminal of the electric field called the cathode	They get attracted to the positive terminal of the electric field called the anode
They have more protons and fewer electrons	They have more electrons and fewer protons
They are smaller in size than anions due to more force of attraction	They are larger than cations due to less force of attraction
Organic cations are called carbocations	Organic anions are called carbanions
They occupy the space between two anions in the crystal lattice	They usually occupy the most of the space of a crystal lattice
Their atoms have very less value of electronegativity	Their atoms have a large value of electronegativity
They have less number of valence electrons	They have more number of valence electrons
Eg. $N{{a}^{+}},M{{g}^{2+}},A{{l}^{3+}}$	Eg. $C{{l}^{-}},{{O}^{2-}},P{{O}_{4}}^{3-}$