First 20 Elements of the Periodic Table_Electronics_News

Get essential facts about the first 20 elements, all in one convenient place, including the name, atomic number, atomic mass, element symbol, group, and electron configuration. If you need detailed facts about these elements or any of the higher numbered ones, start with the clickable periodic table.

01 of 20

Hydrogen

Hydrogen is the first element on the periodic table. William Andrew / Getty Images

Hydrogen is a nonmetallic, colorless gas under ordinary conditions. It becomes an alkali metal under extreme pressure.

Atomic Number: 1

Symbol: H

Atomic Mass: 1.008

Electron Configuration: 1s¹

Group: group 1, s-block, nonmetal

02 of 20

Helium

Helium is the second element on the periodic table. Science Picture Co / Getty Images

Helium is a light, colorless gas that forms a colorless liquid.

Atomic Number: 2

Symbol: He

Atomic Mass: 4.002602(2)

Electron Configuration: 1s²

Group: group 18, s-block, noble gas

03 of 20

Lithium

Lithium is the lightest metal on the periodic table. Science Picture Co / Getty Images

Lithium is a reactive silver 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

04 of 20

Beryllium

Beryllium, atomic number 4. Beryllium is a lightweight, corrosion-resistant metallic element. Lester V. Bergman / Getty Images

Beryllium is a shiny gray-white metal.

Atomic Number: 4

Symbol: Be

Atomic Mass: 9.0121831(5)

Electron Configuration: [He] 2s²

Group: group 2, s-block, alkaline earth metal

05 of 20

Boron

Boron, a soft, amorphous or crystalline nonmetallic element, used in flares and nuclear reactor control rods. Lester V. Bergman / Getty Images

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

06 of 20

Carbon

Forms of carbon including a coal, charcoal, graphite and diamonds. Dave King / Getty Images

Carbon takes several forms. It's usually a gray or black solid, although diamonds may be 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

07 of 20

Nitrogen

Nitrogen (Chemical Element). Science Picture Co / Getty Images

Nitrogen is a colorless gas under ordinary conditions. It cools to form a colorless liquid and solid forms.

Atomic Number: 7

Symbol: N

Atomic Mass: 14.007

Electron Configuration: [He] 2s² 2p³

Group: group 15 (pnictogens), p-block, nonmetal

08 of 20

Oxygen

Oxygen (Chemical Element). Science Picture Co / Getty Images

Oxygen is a colorless gas. Its liquid is blue. Solid oxygen may be any of several colors, including red, black, and metallic.

Atomic Number: 8

Symbol: O

Atomic Mass: 15.999 or 16.00

Electron Configuration: [He] 2s² 2p⁴

Group: group 16 (chalcogens), p-block, nonmetal

09 of 20

Fluorine

Fluorine (Chemical Element). Science Picture Co / Getty Images

Fluorine is a pale yellow gas and liquid and bright yellow solid. The solid may be either opaque or translucent.

Atomic Number: 9

Symbol: F

Atomic Mass: 18.998403163(6)

Electron Configuration: [He] 2s² 2p⁵

Group: group 17, p-block, halogen

10 of 20

Neon

Neon (Chemical Element). Science Picture Co / Getty Images

Neon is a colorless gas that emits a characteristic 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

11 of 20

Sodium

Sodium (Chemical Element). Science Picture Co / Getty Images

Sodium is a soft, silvery-white metal.

Atomic Number: 11

Symbol: Na

Atomic Mass: 22.98976928(2)

Electron Configuration: [Ne] 3s¹

Group: group 1, s-block, alkali metal

12 of 20

Magnesium

Magnesium, metal fern-like crystallization from melt and Mg scrap (Blue background).Magnesium is a chemical element with the symbol Mg and atomic number 12. Lester V. Bergman / Getty Images

Magnesium is a shiny gray metal.

Atomic Number: 12

Symbol: Mg

Atomic Mass: 24.305

Electron Configuration: [Ne] 3s²

Group: group 2, s-block, alkaline earth metal

13 of 20

Aluminum

Pure aluminum chemical element. Kerstin Waurick / Getty Images

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

14 of 20

Silicon

Silicon (Chemical Element). Science Picture Co / Getty Images

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

15 of 20

Phosphorus

Phosphorus (Chemical Element). Science Picture Co / Getty Images

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

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Sulfur

Native Sulfur. Scientifica / Getty Images

Sulfur is a yellow solid.

Atomic Number: 16

Symbol: S

Atomic Mass: 32.06

Electron Configuration: [Ne] 3s² 3p⁴

Group: group 16 (chalcogens), p-block, nonmetal

17 of 20

Chlorine

Chlorine (Chemical Element). Science Picture Co / Getty Images

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

18 of 20

Argon

Argon (Chemical Element). Science Picture Co / Getty Images

Argon is a colorless gas, liquid, and solid. 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

19 of 20

Potassium

Potassium (Chemical Element). Science Picture Co / Getty Images

Potassium is a reactive, silvery metal.

Atomic Number: 19

Symbol: K

Atomic Mass: 39.0983(1)

Electron Configuration: [Ar] 4s¹

Group: group 1, s-block, alkali metal

20 of 20

Calcium

Calcium (Chemical Element). Science Picture Co / Getty Images

Calcium is a dull silver 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