Argon vs Potassium

Side-by-side comparison of Argon (Ar, element 18) and Potassium (K, element 19) by atomic structure and physical properties.

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Property	Ar Argon	K Potassium
Atomic number	18	19
Symbol	Ar	K
Name	Argon	Potassium
Category	noble-gas	alkali-metal
Standard Atomic Weight	39.948 u	39.0983 u
Period	3	4
Group	18	1
Block	p	s
Phase at STP	Gas	Solid
Electron configuration	[Ne]3s23p6	[Ar]4s1
Oxidation states	[0]	[-1, 1]
Electronegativity (Pauling)	N/A	0.82
Electron affinity	-1 eV	0.5014 eV
Density	1.7837 kg/m³	890 kg/m³
Melting point	-189.35 °C	63.38 °C
Boiling point	-185.85 °C	758.85 °C
Discovery year	1894	1807

Key Differences

Property	Ar Argon	K Potassium
Standard Atomic Weight	39.948 u ↑ higher	39.0983 u ↓ lower
Density	1.7837 kg/m³ ↓ lower	890 kg/m³ ↑ higher
Melting point	-189.35 °C ↓ lower	63.38 °C ↑ higher
Boiling point	-185.85 °C ↓ lower	758.85 °C ↑ higher
Electron affinity	-1 eV ↓ lower	0.5014 eV ↑ higher
Period	3	4
Group	18	1
Block	p	s
Category	noble-gas	alkali-metal
Phase at STP	Gas	Solid
Electron configuration	[Ne]3s23p6	[Ar]4s1
Discovery year	1894	1807