Compare Elements

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

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Element comparison
Property H Hydrogen Cs Cesium
Atomic Number 1 lower 55 lower
Symbol H different Cs different
Name Hydrogen different Cesium different
Atomic Mass 1.008 lower 132.9055 lower
Category Reactive Nonmetals different Alkali Metals different
Period 1 lower 6 lower
Group 1 same value 1 same value
Block s-Block same value s-Block same value
Standard State Gas different Solid different
Electronegativity 2.2 higher 0.79 higher
Atomic Radius 120 lower 343 lower
Ionization Energy 13.598 higher 3.894 higher
Electron Affinity 0.754 higher 0.472 higher
Oxidation States +1, -1 different +1 different
Melting Point 13.81 K (-259.34 °C) lower 301.59 K (28.44 °C) lower
Boiling Point 20.28 K (-252.87 °C) lower 944 K (670.85 °C) lower
Density 0.0001 lower 1.93 lower
Electron Configuration 1s1 different [Xe]6s1 different
Year Discovered 1766 different 1860 different

higher lower