The commonly adopted systems for naming organic compounds are:
(i) Common or Trivial system: In this system, the name of the organic compound is based on its origin/ history or some property. Though common names are short and easy to remember, yet a particular compound may be given a number of names. e.g. methyl alcohol is named wood-spirit because it is obtained by destructive distillation of wood.
2. IUPAC system: This is the best system for naming the aliphatic organic compounds. To evolve a systematic method of nomenclature, the international group of chemists have several conferences and recommended the most definite set of organic nomenclature rules called International Union of Pure and Applied Chemistry rules (IUPAC rules). In the IUPAC system, name of organic compound consists of three parts:
(i) Word root       (ii) Prefix            (iii) Suffix.

(i) Word root:The word root represents the number of the carbon atoms present in the chain. Depending upon the number of carbons in the longest chain, the compound is assigned a word root as:

Chain length	Word root	Chain length	Word root
C1	Meth	C6	Hex
C2	Eth	C7	Hept
C3	Prop	C8	Oct
C4	But	C9	Non
C5	Pent	C10	Dec

(ii) Prefix. There are many groups (called substituents) which are not regarded as functional groups in the IUPAC names of a compound. These are called prefixes. These are put before the word root. Some of the prefixes are given below:

(iii) Suffix: The word root is linked to suffix which may be primary followed by secondary.
(a) Primary suffix: A primary suffix is added after the word root to indicate the nature of carhon-carhon bonds. These are piven below:

Nature of bond	Primary suffix	General name
C–C single bond	–ane	Alkane
C = C double bond	–ene	Alkene
C≡ C triple bond	–yne	Alkyne

(b) Secondary suffix: A secondary suffix is added after the primary suffix to indicate the nature of the functional group. These are given below:

A complete IUPAC name of an organic compound may be represented as:
Prefix + Word root + Primary suffix + Secondary suffix
For example, the complete IUPAC name of the compound

(i) Prefix: Bromo
(ii) Word root: Pent
(iii) Primary suffix: yne
(iv) Secondary suffix: oic acid
∴   Complete name of the compound is 4- Bromopent-2 yne-1-oic acid.
Here 4, 2 and 1 represent the positions of prefix, primary suffix and of the secondary suffix in the carbon atom chain.

Alkanes or paraffin are saturated hydrocarbons having C–C and C–H bonds in their molecules. These are represented by the general formula C_nH_2n+2 where n may have value 1, 2, 3, 4......etc.
There is hardly any difference between IUPAC and common names of the members except that prefix n-(normal or straight chain) is used for common names of alkanes with four or more carbon atoms present in straight chains. The common name of the compound is written in the bracket.
When

n = 1 CH₄ Methane (Methane)
n = 2 C₂H₆ Ethane (Ethane)
n = 3 C₃H_g Propane (Propane)
n = 4 C₄H₁₀ Butane (n-Butane)
n = 5 C₅H₁₂ Pentane (n-Pentane)
n = 6 C₆H₁₄ Hexane (n-Hexane)
n = 7 C₇H₁₆ Heptane (n-Heptane)
n = 8 C8H₁₈ Octane (n-Octane)
n = 9 C₉H₂₀ Nonane (n-Nonane)
n=10 C₁₀H₂₂ Decane (n-Decane)