Question

:How do you determine ionic size?

Answer 1

Hint: Ions are defined as a species that contains positive or negative charge. All the ions either have more number of protons than electrons or more number of electrons that protons in their atomic structure. Positive charges are those that contain more number of protons than electrons and the negative charges are those that contain more number of electrons than protons.

Complete step-by-step answer:The ions that contain positive charge are known as cations. For example, $N{{a}^{+}},{{K}^{+}},M{{g}^{2+}}$ and so on. The ions that contain negative charge are known as anions. For example, ${{F}^{-}},C{{l}^{-}},B{{r}^{-}}$ and so on.
Ionic radius is defined as the distance from the nucleus of an ion to the electron cloud. The ionic size of a cation will be smaller than that of the parent atom, because they lose its electrons while their nuclear charge remains the same. The remaining electrons are held tightly by the protons in the nucleus and therefore decrease the size of the cation. Anions are larger in size as compared to parent atoms. The reason behind this is when an atom gains an electron, then there will be an increase in total number of electrons which creates more repulsion between the electrons and hence overshadows the net effective nuclear charge.
The size of both the parent atom and ion will increase when the principal quantum increases. If there is an increase in the nuclear charge, then there will be a decrease in the ionic size.

Note:It is important to know that the electrostatic force of attraction, that is formed between a cation, which is positively charged and an anion, which is negatively charged, are the driving force behind the formation of ionic bonds. The ionic bond formed between the two oppositely charged ions result in the formation of an ionic compound.