Facts about Elements and Periodic Table

Facts about Elements

What is an 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.

Fact to remember Name of the element
Atoms of elements can have different number of electrons and neutrons.
A variant of an element with different number of neutrons is known as itsIsotope
Different physical form of an element is known as its (e.g. graphite and diamond)Allotrope
Element most abundant in the UniverseHydrogen
Element most abundant in the human bodyOxygen
Element which forms more than 10 million compoundsCarbon
Element with the lowest melting and boiling pointHelium
Element with the highest melting pointCarbon
Element with the highest boiling pointTungsten
Element with highest densityOsmium
Element with lowest densityHydrogen
Element with highest electronegativityFlourine
Element with lowest electronegativity (highest electropositivity)Francium
The first element to be produced artificiallyTechnitium
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 EarthHelium
The non-metallic element which is liquid at room temperatureBromine
The metallic element which is liquid at room temperatureMercury
The most reactive elementFlourine

Facts about Periodic Table

Reasons for creating the Periodic Table

The Periodic Table was created to organize and categorize the known chemical elements based on their properties and to understand the relationship between the elements.

The Periodic Table was created by Dmitry Mendeleyev, a Russian chemist and professor in 1869.
The table created by Mendeleyev had 63 known elements. He arranged these elements based on their atomic weights and chemical elements. The table had gaps for elements which could be discovered in future.
The modern periodic table has seven rows or periods.
It has room only for 118 elements. The last element with atomic number of 118 is Oganesson
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 modern 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.


Select the right answer

1. Which element has the highest density?

2. Which is the most electronegative element?

3. Graphite and Diamond are

4. Which is the most abundant element in Universe?

5. Isotopes differ in number of -

6. Which element has the highest boiling point?

7. Which of the following is liquid at room temperature?


Quiz on Periodic Table


Select the right answer

1. How many rows does the Periodic Table contain?

2. In which group are Chlorine, Bromine etc. classified?

3. What is the range of atomic numbers of Lanthanides?

4. To which group do the Noble gases belong?

5. Which is the element with 118 atomic number?

6. How many columns does the Periodic Table have?

7. What is the range of atomic numbers of Actinides?