Facts about Periodic Table

The Periodic Table was created by Dmitry Mendeleyev, a Russian chemist and professor in 1869.
The Periodic Table has seven rows or periods.
The present Periodic Table has room only for 118 elements.
Lanthanides is a group of 15 elements from atomic number 57 to 71. Together with Scandium and Yttrium they are known as rare earth elements.
Rare earth elements which are 17 in number are actally not rare. Most of them are commonly found
Actinides is a group of 15 elements from atomic number 89 to 103. All actinides are radioactive.
The Periodic Table has 18 columns or groups. Some important groups are listed below.
Group 1 - Alkali metals or Lithium group consists of Lithium, Sodium, Potassium, Rubidium, Cesium and Francium. Hydrogen is not an alkali metal even though it is listed in the first column.
Group 2 - Alkaline earth metals or Beryllium group consists of Beryllium, Magnesium, Calcium, Strontium, Barium and Radium.
Group 15 - Pnictogens or Nitrogen group consists of Nitrogen, Phosphorus, Arsenic, Antimony, Bismuth and Moscovium.
Group 16 - Chalcogens or Oxygen group consists of Oxygen, Sulphur, Selenium, Tellurium, Polonium and Livermorium.
Group 17 - Halogens or Flourine group consists of Flourine, Chlorine, Bromine, Iodine, Astatine and Tennessine.
Group 18 - Noble gases or Helium or Neon group consists of Helium, Neon, Argon, Krypton, Xenon, Radon and Oganesson.