The Periodic Table

The Periodic Table was not created by just one person but by multiple people. However, Dmitri Mendeleev is credited as the founder because he took previous data, arranged the elements in a table, and even predicted those that would appear in later years. Mendeleev arranged the elements according to their atomic weight. If they were not in order, it was not in the grouping.

History

In 1789, Antonie Lavoisier grouped the elements according to whether they were metals or nonmetals. Johann Dobereiner founded the elements' physical and chemical properties. This led to the discovery of the triads. A discovery was made when it was revealed that elements would be decided in comparison with element 1, hydrogen. John Newlands only used the existing elements and rearranged them according to increasing atomic masses. The law of octaves was that every eight elements had a similar property. With all the prior knowledge, Mendeleev was able to create the periodic table.

The Periodic Table

There are a total of 118 elements currently on the periodic table. The columns of the periodic table are called groups, which have similar properties. The rows of the periodic table are called periods, and they do not have similar properties. The purpose of the periodic table is to provide data for research. The first group of the periodic table is called Alkali metals. The Alkali metals all have one electron they are trying to get rid of and are highly reactive. The second group is called the Alkaline Earth metals, and they have two valence electrons. Group 17 is the Halogens, and group 18 is the Noble gases. There is a zig-zag split on the right side of the periodic table that splits metals from nonmetals. Metals are most common on the periodic table, while semi-metals are the least common. There are also two rows of elements, lanthanides, and actinides, which are listed on the table but are at the bottom due to limited space.

Properties of Metals, Nonmetals, and Semi-metals

Metals are conductors of heat and electricity. They also have high boiling and melting points. Metals tend to be dense, malleable, and ductile. Nonmetals are the complete opposite of metals, they are not conductors and are brittle and dull. Metalloids, another name for semi-metals, are in between, they are semiconductors and can be shiny and dull but are brittle like nonmetals. Knowing these characteristics of different elements helped the invention of the Periodic Table. There might even be more elements that have not been discovered.

Source:

Libretexts. “2.5: The Periodic Table.” Chemistry LibreTexts, 8 Sept. 2020, chem.libretexts.org/Courses/University_of_Missouri/MU%3A__1330H_(Keller)/02._Atoms_Molecules_and_Ions/2.5%3A_The_Periodic_Table.