First 20 Elements

The first 20 elements of the periodic table have been tabulated below, along with their symbols and atomic numbers.

Atomic Number Element Symbol
1 Hydrogen H
2 Helium He
3 Lithium Li
4 Beryllium Be
5 Boron B
6 Carbon C
7 Nitrogen N
8 Oxygen O
9 Fluorine F
10 Neon Ne
11 Sodium Na
12 Magnesium Mg
13 Aluminium Al
14 Silicon Si
15 Phosphorus P
16 Sulfur S
17 Chlorine Cl
18 Argon Ar
19 Potassium K
20 Calcium Ca

What Information does the Atomic Number of an Element Provide?

The atomic number of an element provides insight into the number of protons that exist inside the nuclei of the atoms of that element and also into the number of electrons that surround these nuclei. For example, the atomic number of sodium is 11. This implies that the nucleus of the sodium atom contains 11 protons and is surrounded by a total of 11 electrons. Since the atomic number of an atom is equal to the number of electrons it contains, the electronic configuration of the element can be determined just by knowing its atomic number.

It is important to note that the number of neutrons that exist in the nucleus of an atom cannot be determined by its atomic number. Different isotopes of an element may have the same number of protons and electrons (since they have the same atomic number), but they may have varying numbers of neutrons. For example, a sodium atom may have 11, 12, or 13 neutrons (based on the isotope) but will always have 11 protons and 11 electrons.

Why is Potassium denoted by the symbol ‘K’ and Sodium by the symbol ‘Na’?

The symbol of potassium is ‘K’ because it is derived from the medieval Latin name for the element, which was ‘Kalium’. Similarly, the symbol for the element sodium is ‘Na’ because it is used to denote its older name ‘Natrium’. Several other elements have symbols denoting their old names. A few such examples have been listed below.

  • The symbol of iron is ‘Fe’, which denotes the Latin name ‘Ferrum’.
  • The symbol of copper is ‘Cu’, which denotes the Latin name ‘Cuprum’.
  • The symbol of silver is ‘Ag’, which denotes the Latin name ‘Argentum’.
  • The symbol of tin is ‘Sn’, which denotes the Latin name ‘Stannum’.
  • The symbol of antimony is ‘Sb’, which denotes the Latin name ‘Stibium’.
  • The symbol of tungsten is ‘W’, which denotes the German name ‘Wolfram’.
  • The symbol of gold is ‘Au’, which denotes the Latin name ‘Aurum’.
  • The symbol of mercury is ‘Hg’, which denotes the Latin name ‘Hydrargyrum’.
  • The symbol of lead is ‘Pb’, which denotes the Latin name ‘Plumbum’.

To learn more about the first 20 elements and to access more data pages on the chemical elements, such as a list of all 118 elements with their symbols and atomic numbers, register with BYJU’S and download the mobile application on your smartphone.

Take up a quiz on First 20 Elements


  1. What is the chemical name for salt

    1. The chemical name of common salt is sodium chloride. It’s chemical formula is NaCl

    2. Chemical name of common salt is (NaCl)

  2. Please give me the electronic structure of first 20 elements

  3. How to remember the 20 elements easily

    1. The ‘secret’ to memorizing is visualization and association. You’ve ever watched someone memorize a deck of playing cards in minutes, and dreamed about what you could do with a memory like that.

      Click here to learn about the Atomic Mass of Elements

  4. what is the chemical name of sugar.

    1. Sucrose is common sugar with a formula of C12H22O11. Click here to learn about the Sucrose – C12H22O11

  5. Very beautiful information. Very useful in future. Like It

  6. I Love chemistry

  7. What is the chemical name of oxygen

    1. Priestley, however, called oxygen “dephlogisticated air”, and did not recognize it as a chemical element.

  8. i really appreciates your effort and concerned, thank you

  9. How was Gravity Formed?

    1. Click here to learn more about Gravity and Gravitational Force.

  10. What is chemical name of paper

    1. Paper is ground up wood pulp, which is then processed, frequently bleached and other chemicals might be added to make a desired colour or smoothness. Cellulose, a primary component, has a chemical formula, (C6H10O5)n, but paper is too much of a mixture to have a single chemical formula.

  11. Very helpful this cleared all my doubts

  12. What is chemical reaction

    1. Chemical reaction, a process in which one or more substances, the reactants, are converted to one or more different substances, the products.

  13. What is Atomicity

    1. Atomicity is defined as the total number of atoms that constitute a molecule.

  14. Why are chemical symbols useful ?

    1. Chemical symbols are used to standardize the ‘language of chemistry’ and to identify elements and atoms in a chemical formula easily. Chemical symbols consist of one or two letters, most often derived from the name of the element.

  15. why does sodium react vigorously when kept in open?

    1. Sodium is a highly reactive metal and reacts vigorously with the oxygen, carbon dioxide and moisture present in the air such that it may even cause a fire. To prevent this explosive reaction, Sodium is kept immersed in kerosene because Sodium doesn’t react with kerosene.

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