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Ways to Group the Elements of the Periodic Table

The periodic table is a way of organizing elements according to their atomic structure and physical properties. Once you understand the meaning of the lines and columns, it becomes fairly easy to find your way around this seemingly mysterious block of letters and numbers. For a visual representation of the periodic table along with descriptions of the various elements, see Resources.

Orbitals
- All atoms have electrons which orbit around their nucleus. The electron orbital refers to how far away from the nucleus an electron is. The horizontal rows in the periodic table indicate the number of orbitals an element has. The elements across the top---hydrogen and helium---have only one electron orbital, while elements on the second line have two, and on down to seven, which is the maximum known number of orbitals for any element. These lines are called "periods," hence the name "periodic table."
Groups
- The vertical columns on the table are called groups. The group an element is in indicates how many electrons it has in its outer most orbital. Thus the first column on the table, which includes such elements as lithium and potassium, has one electron in its outermost orbital. The second column has two. However, this system skips the middle ten columns, using only the two columns on the far right and the six on the far left. Two separate rows listed below do not fall into groups neatly either.
Transition Metals
- The center section of the periodic table (the one that doesn't fit into groups) and the two rows below it---elements 57 through 103---are known as transition metals. The electrons of transitional metals do not fit into the same patterns as the other elements. They have more electrons in certain orbitals than they should and behave in different ways. Whereas the first 18 elements follow set rules, transition metals are not easily explained or described.
Families
- Another way of grouping elements is not by their atomic structure by their physical properties. This could be density, boiling or melting point and ability to conduct heat or electricity. In most simple terms, every element is either a metal or a gas. From the left of the table, you have alkali metals, soft shiny metals that explode in water; alkaline earth metals, which include calcium and magnesium; transition metals; more metals and minerals such as carbon and silicon; halogen gases; and inert gases, on the very right. Halogen gases easily react to and combine with other elements, while inert gases do not.

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