Compare Elements

Compare two chemical elements side by side across 19 atomic and physical properties.

Swap
Element comparison
Property K Potassium Cs Cesium
Atomic Number 19 lower 55 lower
Symbol K different Cs different
Name Potassium different Cesium different
Atomic Mass 39.0983 lower 132.9055 lower
Category Alkali Metals same value Alkali Metals same value
Period 4 lower 6 lower
Group 1 same value 1 same value
Block s-Block same value s-Block same value
Standard State Solid same value Solid same value
Electronegativity 0.82 higher 0.79 higher
Atomic Radius 275 lower 343 lower
Ionization Energy 4.341 higher 3.894 higher
Electron Affinity 0.501 higher 0.472 higher
Oxidation States +1 same value +1 same value
Melting Point 336.53 K (63.38 °C) higher 301.59 K (28.44 °C) higher
Boiling Point 1032 K (758.85 °C) higher 944 K (670.85 °C) higher
Density 0.89 lower 1.93 lower
Electron Configuration [Ar]4s1 different [Xe]6s1 different
Year Discovered 1807 different 1860 different

higher lower