First 20 Elements of the Periodic Table – Names and Symbols

The first 20 elements of the periodic table are hydrogen, helium, lithium, beryllium, boron, carbon, nitrogen, oxygen, fluorine, neon, sodium, magnesium, aluminum, silicon, phosphorus, sulfur, chlorine, argon, potassium, and calcium. Their atomic numbers range from 1 to 20. Here is the complete list with element symbols, atomic numbers, atomic masses, electron configurations, and a printable study sheet.

It’s handy knowing the first 20 elements of the periodic table. Around 99% of the mass of the human body is made of six of these elements. The first 20 elements are also a good overview of the different element groups. These elements occur in most everyday chemical reactions.

List of the First 20 Elements

This is a list of the first 20 elements in order of increasing atomic number. The atomic number is the number of protons in atoms of each element. The first 20 elements and their symbols are:

First 20 Elements PDF Worksheet

Download the free First 20 Elements of the Periodic Table Worksheet. This two-page printable tests the names, chemical symbols, and periodic table positions of elements 1 through 20. The second page mixes the elements rather than listing them in atomic number order for more effective recall practice.

Key Takeaways: First 20 Elements

• The first 20 elements have atomic numbers 1 through 20.
• Hydrogen (H) is element 1 and calcium (Ca) is element 20.
• Atomic number equals the number of protons in an atom of an element.
• Learning the names, symbols, and atomic numbers of the first 20 elements provides a useful foundation for studying chemistry.

What Makes Them Elements?

At a minimum, matter contains one or more protons to be an element. The number of protons identifies the element. Atoms of elements may also contain neutrons together with protons to form the atomic nucleus. Samples with the same number of protons but different numbers of neutrons are all the same element but are different isotopes. Atoms also have electrons that orbit around the nucleus. Changing the number of electrons around an atom makes it an ion, but doesn’t change its identity as an element. Elements are called the building blocks of matter because their atoms can’t be divided into smaller parts using any chemical means. Atoms of elements can form chemical bonds with one another to form compounds.

Element Names and Symbols

Three ways of identifying elements are using their atomic number, element name, or element symbol. The symbol is a one- or two-letter abbreviation of the name. However, some symbols refer to old element names. For example, the symbol for sodium is Na. This refers to the Latin word natrium, which was the old name for caustic soda. The symbol of potassium is K, which stands for the Latin word kalium, which meant alkali or potash. The first letter of an element symbol is capitalized. When there is a second letter, it is lower case.

The Element Song

Now that you know the first 20 elements, why not learn the names of several more? Try singing “The Element Song” or follow along!

Uses of the First 20 Elements of the Periodic Table

The first twenty elements are abundant in daily life:

1. Hydrogen (H): Used in the production of ammonia for fertilizers and as rocket fuel. It is also a key component in fuel cells and hydrogen-powered vehicles.
2. Helium (He): Common in balloons and airships due to its low density and non-flammability. It is also essential for cooling superconducting magnets in MRI machines.
3. Lithium (Li): Widely used in rechargeable batteries for electronics and electric vehicles. It is also used in mood-stabilizing drugs for bipolar disorder.
4. Beryllium (Be): Used in aerospace materials due to its high strength-to-weight ratio and in X-ray windows for its transparency to X-rays.
5. Boron (B): Found in borosilicate glass and detergents. It is also a neutron absorber in nuclear reactors.
6. Carbon (C): The foundation of organic chemistry, used in steel production, as graphite in pencils, and in diamond cutting tools.
7. Nitrogen (N): Used in ammonia production, fertilizers, and as an inert gas in food packaging. Liquid nitrogen is a refrigerant.
8. Oxygen (O): Essential for respiration and used in medical applications and welding. It is also used in water treatment and steelmaking.
9. Fluorine (F): Used in toothpaste and water fluoridation to prevent tooth decay. It is also a key component in Teflon and refrigerants.
10. Neon (Ne): Famous for its use in neon signs. It is also used in high-voltage indicators and cryogenics.
11. Sodium (Na): Found in table salt (sodium chloride) and used in street lighting and soap production.
12. Magnesium (Mg): Used in lightweight alloys for aircraft and automotive parts. It is an essential nutrient in biological systems.
13. Aluminum (Al): Extensively used in construction, packaging (foil and cans), and transportation due to its lightweight and corrosion resistance.
14. Silicon (Si): Found in semiconductors for electronics and as a key component in glass, concrete, and ceramics.
15. Phosphorus (P): Used in fertilizers, detergents, and safety matches. It is also a critical component of DNA and ATP in living organisms.
16. Sulfur (S): Used in the production of sulfuric acid, fertilizers, and rubber vulcanization. It is also used in gunpowder and insecticides.
17. Chlorine (Cl): Essential in water disinfection and in the production of PVC plastic. It is also used in bleach and cleaning products.
18. Argon (Ar): Common as an inert shielding gas in welding and in incandescent light bulbs to protect the filament.
19. Potassium (K): Vital for plant growth, used in fertilizers, and in potassium-based salts for soap production.
20. Calcium (Ca): Found in construction materials like cement and lime. It is essential for bone health and is used in food and supplements.

A Closer Look at the First 20 Elements

Here is a brief description of each of the first 20 elements, including appearance, state of matter under normal temperature and pressure, atomic number, symbol, atomic mass, electron configuration, and element group:

Hydrogen

• Hydrogen is a nonmetallic, colorless gas under ordinary conditions. Under extreme pressure, it becomes an alkali metal. There are three isotopes of this element, which differ in the number of neutrons in their atoms. The most common isotope is protium. The others are deuterium and tritium.
• Atomic Number: 1
• Symbol: H
• Atomic Mass: 1.008
• Electron Configuration: 1s¹
• Group: group 1, s-block, nonmetal

Helium

• Helium is a light, colorless gas.
• Atomic Number: 2
• Symbol: He
• Atomic Mass: 4.002602(2)
• Electron Configuration: 1s²
• Group: group 18, s-block, noble gas

Lithium

• Lithium is a reactive silver solid metal.
• Atomic Number: 3
• Symbol: Li
• Atomic Mass: 6.94 (6.938–6.997)
• Electron Configuration: [He] 2s¹
• Group: group 1, s-block, alkali metal

Beryllium

• Beryllium is a shiny gray-white solid metal.
• Atomic Number: 4
• Symbol: Be
• Atomic Mass: 9.0121831(5)
• Electron Configuration: [He] 2s²
• Group: group 2, s-block, alkaline earth metal

Boron

• Boron is a gray solid with a metallic luster.
• Atomic Number: 5
• Symbol: B
• Atomic Mass: 10.81 (10.806–10.821)
• Electron Configuration: [He] 2s² 2p¹
• Group: group 13, p-block, metalloid

Carbon

• Carbon is a solid that takes several forms, including diamond, graphite, and amorphous carbon. It is black, gray, or colorless.
• Atomic Number: 6
• Symbol: C
• Atomic Mass: 12.011 (12.0096–12.0116)
• Electron Configuration: [He] 2s² 2p²
• Group: group 14, p-block, usually a nonmetal although sometimes considered a metalloid

Nitrogen

• Nitrogen is a colorless gas.
• Atomic Number: 7
• Symbol: N
• Atomic Mass: 14.007
• Electron Configuration: [He] 2s​² 2p³
• Group: group 15 (pnictogens), p-block, nonmetal

Oxygen

• Oxygen is a colorless gas. Its liquid form is blue, while its solid takes many colors, including red, metallic, and black.
• Atomic Number: 8
• Symbol: O
• Atomic Mass: 15.999 or 16.00
• Electron Configuration: [He] 2s² 2p⁴
• Group: group 16 (chalcogens), p-block, nonmetal

Fluorine

• Fluorine is a pale yellow gas and liquid and bright yellow solid.
• Atomic Number: 9
• Symbol: F
• Atomic Mass: 18.998403163(6)
• Electron Configuration: [He] 2s² 2p⁵
• Group: group 17, p-block, halogen

Neon

• Neon is a colorless gas that emits an orange-red glow when excited in an electric field.
• Atomic Number: 10
• Symbol: Ne
• Atomic Mass: 20.1797(6)
• Electron Configuration: [He] 2s² 2p⁶
• Group: group 18, p-block, noble gas

Sodium

• Sodium is a soft, silvery-white solid metal.
• Atomic Number: 11
• Symbol: Na
• Atomic Mass: 22.98976928(2)
• Electron Configuration: [Ne] 3s¹
• Group: group 1, s-block, alkali metal

Magnesium

• Magnesium is a shiny gray solid metal.
• Atomic Number: 12
• Symbol: Mg
• Atomic Mass: 24.305
• Electron Configuration: [Ne] 3s²
• Group: group 2, s-block, alkaline earth metal

Aluminum

• Aluminum is a soft, silver-colored, nonmagnetic metal.
• Atomic Number: 13
• Symbol: Al
• Atomic Mass: 26.9815385(7)
• Electron Configuration: [Ne] 3s² 3p¹
• Group: group 13, p-block, considered a post-transition metal or sometimes a metalloid

Silicon

• Silicon is a hard, blue-gray crystalline solid that has a metallic luster.
• Atomic Number: 14
• Symbol: Si
• Atomic Mass: 28.085
• Electron Configuration: [Ne] 3s² 3p²
• Group: group 14 (carbon group), p-block, metalloid

Phosphorus

• Phosphorus is a solid under ordinary conditions, but it takes several forms. The most common are white phosphorus and red phosphorus.
• Atomic Number: 15
• Symbol: P
• Atomic Mass: 30.973761998(5)
• Electron Configuration: [Ne] 3s² 3p³
• Group: group 15 (pnictogens), p-block, usually considered a nonmetal, but sometimes a metalloid

Sulfur

• Sulfur is a yellow solid, usually found as a crystal or powder.
• Atomic Number: 16
• Symbol: S
• Atomic Mass: 32.06
• Electron Configuration: [Ne] 3s² 3p⁴
• Group: group 16 (chalcogens), p-block, nonmetal

Chlorine

• Chlorine is a pale yellow-green gas under ordinary conditions. Its liquid form is bright yellow.
• Atomic Number: 17
• Symbol: Cl
• Atomic Mass: 35.45
• Electron Configuration: [Ne] 3s² 3p⁵
• Group: group 17, p-block, halogen

Argon

• Argon is a colorless gas, liquid, and solid. It is a gas under ordinary conditions. It emits a bright lilac-purple glow when excited in an electric field.
• Atomic Number: 18
• Symbol: Ar
• Atomic Mass: 39.948(1)
• Electron Configuration: [Ne] 3s² 3p⁶
• Group: group 18, p-block, noble gas

Potassium

• Potassium is a reactive, silvery solid metal.
• Atomic Number: 19
• Symbol: K
• Atomic Mass: 39.0983(1)
• Electron Configuration: [Ar] 4s¹
• Group: group 1, s-block, alkali metal

Calcium

• Calcium is a dull silver solid metal with a faint yellowish cast.
• Atomic Number: 20
• Symbol: Ca
• Atomic Mass: 40.078(4)
• Electron Configuration: [Ar] 4s²
• Group: group 2, s-block, alkaline earth metal

References

• Ball, P. (2004). The Elements: A Very Short Introduction. Oxford University Press. ISBN 978-0-19-284099-8.
• Emsley, J. (2003). Nature’s Building Blocks: An A–Z Guide to the Elements. Oxford University Press. ISBN 978-0-19-850340-8.
• Gray, T. (2009). The Elements: A Visual Exploration of Every Known Atom in the Universe. Black Dog & Leventhal Publishers Inc. ISBN 978-1-57912-814-2.
• IUPAC (1997). “Chemical Element.” Compendium of Chemical Terminology (2nd ed.). doi:10.1351/goldbook.C01022
• Wang, Meng; Huang, W. J.; Kondev, F. G.; Audi, G.; Naimi, S. (March 2021). “The AME 2020 atomic mass evaluation (II). Tables, graphs and references”. Chinese Physics C. 45 (3): 030003. doi:10.1088/1674-1137/abddaf