The very first scientist arrange elements in order is an English chemist, John Newlands. He is the one who pioneered the discover of the periodic table. Newlands arranged the elements by their relative atomic weights in 1863.
The next year in 1864, Dmitri Mendeleev a Russian chemist, came up with the very first version of the peridic table. Unlike John Newlands, Mendeleev put the elements in order by similar properties in stead of their relative atomic mass. Mendeleev left blanks in the periodic table for the elements yet to be discovered.
Glen Seaborg is the last to make changes in the modern periodic table. Seaborg dicovered elements 94 to 102. Element 106 has been named after him.
For the organization of the periodic table, the horizontal rows are called a period. Vertical columns are called families or groups.
Alkali metals: highly reactive metals that are located in group 1 in the periodic table.
Alkaline earth metals: reactive metals that are located in group 2 in the peridoic table
Halogens : Non metals that are highly reactive and react with water, located in group 17.
Noble Gases: odourless, colourless, non metals that have low reactivity because their valence sheels are full. They are in group 18.
Lanthanide Series : elements 57-71
Actinide Series : elements 89-103, all are radioactive.
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