Chemical Species

Chemical Species

Chemical Species are atoms, ions or molecules that can take part in a chemical process

Ions

An atom with a net charge is called an "Ion".

Types

It has 2 types:

1.) Cations                             2.)Anions

Cations

An atom that has a net positive charge is called a "Cation". It is formed by the losing of electron(s) i.e. If an atom with more electronegativity takes away the electron of one atom, then the atom which lost it's electron will have 1 less electron than the number of protons. (Naturally, an atom's number of protons = it's number of electrons.) More positivity and less negativity gives it a net positive charge. For example: Hydrogen cation (H+) and Sodium cation (Na+). The plus sign is written as a superscript meaning it is written in small size on the upper right corner of the symbol.

Anions

An atom that has a net negative charge is called a "Anion". It is formed by the gaining of electron(s) i.e If 2 atoms approach each other such that the electronegativity difference is greater than 1.7, then  the atom with more electronegativity will take away an electron from the atom with lower electronegativity. Now, the highly electronegative atom has 1 more electron than the number of protons. (Naturally, an atom's number of protons = it's number of electrons.) There is more negativity than positivity. So, the atom gains a net negative charge.

Molecular Ions/Poly-atomic Ions

A molecule with a net charge is called a "Molecular Ion" or a "Poly-atomic Ion

' ("Poly" means "many" in the Greek language.) When gases are bombarded with high-energy electrons in a discharge tube, they ionize to give molecular ions.

Cationic Molecular Ion

A molecule with a net positive charge is called a "Cationic Molecular Ion". eg. NH4+
 (4 and plus are written as superscripts.) They are more abundant than anionic molecular ions.

Anionic Molecular Ions

A molecule with a net negative charge is called an "Anionic Molecular Ion". e.g. Hydroxide Symbol OH- (The minus is written as a superscript.) 

Radical/Free Radical

An atom whose number of electrons is equal to an odd number is called a "Radical" or a "Free Radical". They are represented by putting a dot on the upper right corner of the symbol of the element. The are very reactive. The exist naturally e.g. Chlorine and are sometimes by Homolytic Cleavage or Homolysis, a type of Bond Cleavage .(Discussed later) 

Ions

Nitrate Ion (NO3-), a molecular ion

Free Radical