Elements & Periodic Table
WEeb.in Team Science Total Views: 621 Posted: Sep 10, 2019 Updated: Oct 3, 2026
Facts about Elements
| Fact to remember | Name of the element |
|---|---|
| An element is defined by the IUPAC as a pure chemical substance composed of atoms with the same number of protons in the atomic nucleus. All atoms of an element have the same number of protons. | |
| Atoms of elements can have different number of electrons and neutrons. | |
| A variant of an element with different number of neutrons is known as its | Isotope |
| Different physical form of an element is known as its (e.g. graphite and diamond) | Allotrope |
| Element most abundant in the Universe | Hydrogen |
| Element most abundant in the human body | Oxygen |
| Element which forms more than 10 million compounds | Carbon |
| Element with the lowest melting and boiling point | Helium |
| Element with the highest melting point | Carbon |
| Element with the highest boiling point | Tungsten |
| Element with highest density | Osmium |
| Element with lowest density | Hydrogen |
| Element with highest electronegativity | Flourine |
| Element with lowest electronegativity (highest electropositivity) | Francium |
| The first element to be produced artificially | Technitium |
| The most corrosion resistant element (which cannot be affected by water, chemicals or acids) | Iridium |
| The element which was discovered on the Sun before it was found on the Earth | Helium |
| The non-metallic element which is liquid at room temperature | Bromine |
| The metallic element which is liquid at room temperature | Mercury |
| The most reactive element | Flourine |
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. |
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