Compare Elements

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

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Element comparison
Property He Helium Kr Krypton
Atomic Number 2 lower 36 lower
Symbol He different Kr different
Name Helium different Krypton different
Atomic Mass 4.0026 lower 83.8 lower
Category Noble Gases same value Noble Gases same value
Period 1 lower 4 lower
Group 18 same value 18 same value
Block p-Block same value p-Block same value
Standard State Gas same value Gas same value
Electronegativity — no data 3 no data
Atomic Radius 140 lower 202 lower
Ionization Energy 24.587 higher 14 higher
Electron Affinity — no data — no data
Oxidation States 0 same value 0 same value
Melting Point 0.95 K (-272.2 °C) lower 115.79 K (-157.36 °C) lower
Boiling Point 4.22 K (-268.93 °C) lower 119.93 K (-153.22 °C) lower
Density 0.0002 lower 0.0037 lower
Electron Configuration 1s2 different [Ar]4s2 3d10 4p6 different
Year Discovered 1868 different 1898 different

higher lower