What is the basis for the arrangement of the present periodic table?

Answer 1

The periodic law is that the chemical properties of the elements are periodic functions (that is, they repeat again and again) of their atomic numbers. It used to be their atomic weights, but there are small discrepancies in the atomic weight version because of the distribution of stable isotopes of a few elements.

So chemists write the elements out in a line until they get to an element that corresponds to the first. Then they put that element under the first and start a new line. For example, H and He are the first line. Li is a lot like H, so put Li under H and start a new line from there. Next, Na is a lot like Li, so put Na under Li and make that a third line.

Actually, there are several ways to make a periodic table. Some are boxy affairs with Cu put in the same box with K and Zn in the same box with Ca. The most common is a rather strung-out arrangement. There are even cylinders and spirals as people try to show the periodic recurrence of element types.

Answer 2

It mostly goes by atomic number(least to greatest)

Answer 3

groups like 1A, 2A,3A
carbons, halogens, Nobel gasses