Alkali Metals

Potassium 100gr (metal) Atomic Number (Ζ): 19 Atomic weight (A_r): 39.0983 Cas Number: 7440-09-7 https://pubchem.ncbi.nlm.nih.gov/compound/Potassium

Sodium, ₁₁Na

Phase at STP	solid
Melting point	370.944 K ​(97.794 °C, ​208.029 °F)
Boiling point	1156.090 K ​(882.940 °C, ​1621.292 °F)
Density (near r.t.)	0.968 g/cm3
when liquid (at m.p.)	0.927 g/cm3
Critical point	2573 K, 35 MPa (extrapolated)
Heat of fusion	2.60 kJ/mol
Heat of vaporization	97.42 kJ/mol
Molar heat capacity	28.230 J/(mol·K)