Why is it named after the chemical usage of methyl, ethyl, propyl, butyl, pentyl, heptyl, octyl and non-undecyl?

When naming the main chain of organic matter, the carbon atoms in the main chain are less than or equal to 10, and are named after Tiangan (ethylene, propylene, butyl, pentyl, octyl and non-decyl), and those greater than ten are directly named by Chinese characters.

Such as alkanes:

Find the longest carbon chain as the main chain, and name the main chain according to the carbon number. The first ten carbon numbers are represented by heavenly stems (A, B, C, D, E, F, G, N, N), and when the carbon number is greater than ten, they are named after chinese numerals, such as eleven carbons.

From the nearest number of substituent positions: 1, 2, 3 ... (The smaller the number of substituent positions, the better). Numbers represent the positions of substituents. Use-between numbers and chinese numerals.

When there are multiple substituents, the carbon chain with the smallest and longest number of substituents is the main chain, and all substituents are listed in the order of methyl, ethyl and propyl.

When two or more substituents are the same, chinese numerals is added before the substituents: I, II and III, such as dimethyl, and the substituents are juxtaposed separately.