Potassium (K) VS Phosphorus (P)
A definitive side-by-side comparison of two essential element profiles.
VS
Main Differences
Potassium (K) is an element in the alkali metals category with an atomic number of 19. Phosphorus (P) is an element in the nonmetals category with an atomic number of 15.
Phosphorus (P) is 2.1x denser than Potassium (K). Furthermore, Potassium (K) melts at a significantly higher temperature than Phosphorus (P) (a difference of 19.2 Kelvin).
Where do the names come from?
K Potassium (K) Naming History
The name Potassium is derived from the English word ''potash''.
Phosphorus (P) Naming History
The name Phosphorus is derived from the Greek 'phosphoros', meaning bringer of light.
Related Comparisons
Compare
Potassium (K)
Phosphorus (P)
Category
Alkali Metals
Nonmetals
Atomic Number
19
15
Symbol
K
P
Atomic Mass
39.098 u
30.974 u
Group
1
15
Period
4
3
Block
s-block
p-block
Standard State (at 20°C)
solid
solid
Density
0.862 g/cm³
1.823 g/cm³
Melting Point (°C)
63.5°C
44.15°C
Melting Point (°F)
146.3°F
111.47°F
Melting Point (K)
336.53 K
317.3 K
Boiling Point (°C)
759°C
280.5°C
Boiling Point (°F)
1398°F
536.9°F
Boiling Point (K)
1032 K
553.7 K
Year Discovered:
1807
1669
CAS Number
07/09/7440
7723-14-0
Origin of Name:
The name is derived from the English word ''potash''.
The name is derived from the Greek 'phosphoros', meaning bringer of light.