Element 19
Potassium
Alkali metals
Potassium (K) is in the s-block of the periodic table — group 1, period 4.
Potassium is a chemical element with symbol K (derived from Neo-Latin, kalium) and atomic number 19.
Key data
- Atomic number
- 19
- Atomic mass
- 39.098 u
- Group / Period
- 1 / 4
- Block
- s-block
- Phase at STP
- Solid
- Density
- 0.862 g/cm³
- Melting point
- 63.6 °C
- Boiling point
- 758.9 °C
- Electron configuration
- [Ar] 4s1
Periodic table block
Potassium is in the s-block (group 1, period 4). Elements land in the s-block when their highest-energy electrons fill an s subshell — this includes hydrogen, helium, and the reactive metals on the far left of the table.
New to this? Periodic table blocks explained: s, p, d, and f
Common uses
- •Fertilizer
- •Gunpowder (saltpeter)
- •Body fluid balance
Discovery
Year: 1807
Discovered by: Humphry Davy
Frequently asked questions
What is the atomic number of Potassium?
Potassium has atomic number 19. Its symbol is K and its atomic mass is 39.098 u.
What category of element is Potassium?
Potassium is classified as alkali metals. It sits in group 1, period 4 of the periodic table.
What block of the periodic table is Potassium in?
Potassium is in the s-block (group 1, period 4). Its highest-energy electrons occupy the s subshell — you can see this in its electron configuration, [Ar] 4s1.
What is Potassium used for?
Common uses of Potassium include: Fertilizer, Gunpowder (saltpeter), Body fluid balance.
When was Potassium discovered?
Potassium was discovered in 1807 by Humphry Davy.
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