How are groups in the periodic table arranged?

Answer 1

Elements are arranged on the Periodic Table in the order of the atomic number, in groups and periods.

Answer 2

The elements are arranged in the sequence of their increasing atomic numbers into the periodic table, which is arranged in rows and columns, so that elements with similar chemical properties are in the same vertical column.The elements which are in the same columns are said to be in the same group, and they have similar chemical properties.

Answer 3

Left to right is called a period.

Top to bottom is called a group.

With the exception of Hydrogen and Helium which have their own unique properties, each element in a group share similar properties. The most fundamental property they share are that each one has the same number of electrons in their outermost (valence) shell/orbital.

Atoms are arranged from left to right by increasing number of protons in their nucleus. As we move from left to right across a period, atoms get smaller (even though they get heavier). This is due to the fact that more protons with positive charge in the nucleus hold the electrons closer. Atoms get bigger as you move down a group. Atoms are more electronegative (affinity to gain an electron) as you move left to right across a period or up a group. (The exception to this is the last group. These so called "Noble" gases don't really care about electrons. Their valence shell has an octet and they are happy to just be.)

The best way to explain the arrangement of the Periodic Table is by giving an explanation of electron orbitals but this is a bit more advanced. I will briefly give an over-simplified explanation. Electrons can be arranged in different kinds of orbitals, s, p, d, etc.... s orbitals can hold 2 electrons, p orbitals can hold 6 electrons, d orbitals can hold 10 electrons. Each of these orbitals have different levels, 1s, 2s, 4s, etc. The orbitals must fill in a particular order. That order is 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p. These are not manmade rules. This is just what has been observed. Since the 1s orbital can hold 2 electrons you get 1s1. That is hydrogen. Then you get 1s2. That is helium. Then you get 1s2, 2s1, lithium. Since both hydrogen and lithium both have a single electron in the outermost s orbital, they will be placed in the same group. 1s2, 2s2, berillium starts group 2. 1s2 2s2 2p1, boron, 1s2 2s2 2p2, carbon, 1s2 2s2 2p3, Nitrogen, 1s2 2s2 2p4, Oxygen. 1s2 2s2 2p5, Flourine, 1s2, 2s2, 2p6, Neon.

Now it begins to repeat. The next atom is 1s2, 2s2, 2p6, 3s1 (sodium)... since it has 1 electron in its last orbital slot it goes in group 1 under hydrogen and lithium. The next element, magnesium has an orbital of 1s2, 2s2, 2p6, 3s2 and so it goes under berillium. This goes on and on. You will notice that there are 10 elements groups in the middle that we skip at the moment. They will come into play when we introduce d and f orbitals. But each atom is arranged so that the last orbital lines up in groups with atoms of similar final orbitals. That's a lot to take in, and over simplified.

Answer 4

they are arranged by the diffrent properties and proton number

Answer 5

Bohr arrange the elements on the based on their atomic number

Answer 6

There are 7 periods in the periodic table