potassium [Chemical formula, Physical, Chemical Properties and Reactions]

By: Prof. Dr. Fazal Rehman Shamil | Last updated: February 3, 2024

The chemical symbol for potassium is “K”.

Physical Properties of Potassium:

Properties Details
SymbolK
Atomic Number19
Atomic Mass39.0983 u
Phase at Room TemperatureSolid
Melting Point63.38°C
Boiling Point759°C
Density0.86 g/cm³
ColorSilver-white
Crystal StructureBody-centered cubic (BCC)
Electrical ConductivityGood conductor of electricity

Chemical Properties of Potassium:

Properties Details
ReactivityHighly reactive metal, reacts vigorously with water
Oxidation States+1
Flame ColorViolet
Reacts with OxygenBurns with a lilac flame, forming potassium oxide (K₂O)
Reacts with WaterReacts violently with water, releasing hydrogen gas
Reacts with AcidsReacts with acids to produce potassium salts and hydrogen gas
Reacts with HalogensReacts with halogens (e.g., chlorine) to form ionic salts
Reactivity towards OxygenTends to lose electrons to form potassium oxide

Reaction of potassium with Alkali Metal

Alkali MetalReaction with Potassium
Lithium (Li)2K   and  2LiCl   react and convert into  2KCl   and  2Li
Sodium (Na)2K   and  2NaCl   react and convert into  2KCl   and  2Na
Potassium (K)No reaction (self-reaction)
Rubidium (Rb)2K   and  2RbCl   react and convert into  2KCl   and  2Rb
Cesium (Cs)2K   and  2CsCl   react and convert into  2KCl   and  2Cs
Francium (Fr)2K   and  2FrCl   react and convert into  2KCl   and  2Fr

Reaction of potassium with Transition Metal

Transition MetalReaction with Potassium
Iron (Fe)3K   and  2FeCl₂   react and convert into  2KCl   and  2KFe
Copper (Cu)2K   and  CuCl₂   react and convert into  2KCl   and  Cu
Silver (Ag)2K   and  AgCl   react and convert into  2KCl   and  Ag
Nickel (Ni)2K   and  NiCl₂   react and convert into  2KCl   and  Ni
Palladium (Pd)2K   and  PdCl₂   react and convert into  2KCl   and  Pd
Platinum (Pt)2K   and  PtCl₂   react and convert into  2KCl   and  Pt
Gold (Au)2K   and  AuCl₃   react and convert into  2KCl   and  Au
Titanium (Ti)No reaction (under normal conditions)
Chromium (Cr)No reaction (under normal conditions)
Manganese (Mn)No reaction (under normal conditions)
Cobalt (Co)No reaction (under normal conditions)
Zinc (Zn)No reaction (under normal conditions)

Reaction of potassium with Non-Transition Metal

Non-Transition MetalReaction with Potassium
Aluminum (Al)2K   and  2AlCl₃   react and convert into  2KCl   and  2Al
Gallium (Ga)2K   and  2GaCl₃   react and convert into  2KCl   and  2Ga
Indium (In)2K   and  2InCl₃   react and convert into  2KCl   and  2In
Tin (Sn)2K   and  SnCl₂   react and convert into  2KCl   and  Sn
Thallium (Tl)2K   and  2TlCl₃   react and convert into  2KCl   and  2Tl
Lead (Pb)2K   and  PbCl₂   react and convert into  2KCl   and  Pb
Bismuth (Bi)2K   and  2BiCl₃   react and convert into  2KCl   and  2Bi
Antimony (Sb)2K   and  SbCl₃   react and convert into  2KCl   and  Sb
Selenium (Se)2K   and  Se   react and convert into  K₂Se
Tellurium (Te)2K   and  Te   react and convert into  K₂Te
Phosphorus (P)4K   and  P₄   react and convert into  4KP
Sulfur (S)2K   and  S₈   react and convert into  K₂S₈
Oxygen (O)4K   and  O₂   react and convert into  2K₂O
Nitrogen (N)No reaction (under normal conditions)
Hydrogen (H)2K   and  2H₂O   react and convert into  2KOH   and  H₂

Reaction of potassium with Non-Metal

Non-MetalReaction with Potassium
Hydrogen (H)2K   and  2H₂O   react and convert into  2KOH   and  H₂
Carbon (C)2K   and  C₆H₆   react and convert into  2KC₆H₆ (Potassium cyclohexyl)
Nitrogen (N)2K   and  N₂   react and convert into  2KN
Oxygen (O)4K   and  O₂   react and convert into  2K₂O
Fluorine (F)2K   and  F₂   react and convert into  2KF
Chlorine (Cl)2K   and  Cl₂   react and convert into  2KCl
Bromine (Br)2K   and  Br₂   react and convert into  2KBr
Iodine (I)2K   and  I₂   react and convert into  2KI
Sulfur (S)2K   and  S₈   react and convert into  K₂S₈
Phosphorus (P)4K   and  P₄   react and convert into  4KP
Selenium (Se)2K   and  Se   react and convert into  K₂Se
Tellurium (Te)2K   and  Te   react and convert into  K₂Te
Boron (B)2K   and  B₂H₆   react and convert into  2KBH₆ (Potassium borohydride)
Silicon (Si)2K   and  SiCl₄   react and convert into  2KCl   and  Si
Hydrogen sulfide2K   and  H₂S   react and convert into  2KHS (Potassium hydrosulfide)
Ammonia (NH₃)2K   and  2NH₃   react and convert into  2KNH₂   and  H₂ (Formation of potassium amide and hydrogen)

Reaction of potassium with Metalloid

MetalloidReaction with Potassium
Boron (B)2K   and  B₂H₆   react and convert into  2KBH₆ (Potassium borohydride)
Silicon (Si)2K   and  SiCl₄   react and convert into  2KCl   and  Si
Germanium (Ge)2K   and  GeCl₄   react and convert into  2KCl   and  Ge
Arsenic (As)2K   and  AsCl₃   react and convert into  2KCl   and  As
Antimony (Sb)2K   and  SbCl₃   react and convert into  2KCl   and  Sb
Tellurium (Te)2K   and  Te   react and convert into  K₂Te
Polonium (Po)2K   and  Po   react and convert into  K₂Po