Periodic Table Groups 13-17

Group 13:
Boron Group
Boron (B) - Atomic Number 5
Aluminum (Al) - Atomic Number 13
Gallium (Ga) - Atomic Number 31
Indium (In) - Atomic Number 49
Thallium (Tl) - Atomic Number 81
Group 14:
Carbon Group
Carbon (C) - Atomic Number 6
Silicon (Si) - Atomic Number 14
Germanium (Ge) - Atomic Number 32
Tin (Sn) - Atomic Number 50
Lead (Pb) - Atomic Number 82
Group 15:
Nitrogen Group
Nitrogen (N) - Atomic Number 7
Phosphorus (P) - Atomic Number 15
Arsenic (As) - Atomic Number 33
Antimony (Sb) - Atomic Number 51
Bismuth (Bi) - Atomic Number 83
Group 16:
Oxygen Group or Chalcogens
Oxygen (O) - Atomic Number 8
Sulfur (S) - Atomic Number 16
Selenium (Se) - Atomic Number 34
Tellurium (Te) - Atomic Number 52
Polonium (Po) - Atomic Number 84
Group 17:
Halogens
Fluorine (F) - Atomic Number 9
Chlorine (Cl) - Atomic Number 17
Bromine (Br) - Atomic Number 35
Iodine (I) - Atomic Number 53
Astatine (At) - Atomic Number 85
These groups share similar chemical properties due to the arrangement of electrons in their outermost energy levels. Group 13 elements are often referred to as the "boron group," Group 14 as the "carbon group," Group 15 as the "nitrogen group," and Group 16 as the "oxygen group" or "chalcogens." Group 17 elements are known as the "halogens."

[@kisho2679]

Why cant there be more than 18 groups?

[@sciencechemistry]

The periodic table is organized based on the electronic structure of atoms, specifically the arrangement of electrons in their orbitals. The table is structured to group elements with similar chemical properties together. The reason there are 18 groups is related to the number of electrons that can occupy the principal energy levels (shells) in an atom.
The periodic table consists of periods (rows) and groups (columns). Each period represents a new energy level, and each group represents a column of elements with similar chemical properties. The maximum number of electrons in each energy level is determined by the formula 2n^2, where "n" is the principal quantum number of the energy level. For example, the first energy level (n=1) can hold up to 2 electrons, the second (n=2) can hold up to 8, and so on.
When you sum up the maximum number of electrons accommodated in all the energy levels, you get 2 + 8 + 18 + 32, which equals 60. However, the structure of the periodic table is such that after the 18th group, the pattern starts repeating, and elements in the 19th column would have similar properties to those in the 1st column. This repetition is known as the periodicity of the elements.
So, the decision to limit the number of groups to 18 is based on the electronic structure and the periodic nature of the elements, and it helps organize the elements in a way that reflects their chemical behavior.