Compare Elements

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

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Element comparison
Property Ca Calcium Se Selenium
Atomic Number 20 lower 34 lower
Symbol Ca different Se different
Name Calcium different Selenium different
Atomic Mass 40.08 lower 78.97 lower
Category Alkaline Earth Metals different Reactive Nonmetals different
Period 4 same value 4 same value
Group 2 lower 16 lower
Block s-Block different p-Block different
Standard State Solid same value Solid same value
Electronegativity 1 lower 2.55 lower
Atomic Radius 231 higher 190 higher
Ionization Energy 6.113 lower 9.752 lower
Electron Affinity — no data 2.021 no data
Oxidation States +2 different +6, +4, -2 different
Melting Point 1115 K (841.85 °C) higher 493.65 K (220.5 °C) higher
Boiling Point 1757 K (1483.85 °C) higher 958 K (684.85 °C) higher
Density 1.54 lower 4.809 lower
Electron Configuration [Ar]4s2 different [Ar]4s2 3d10 4p4 different
Year Discovered Ancient different 1817 different

higher lower