Compare Elements

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

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Element comparison
Property Se Selenium K Potassium
Atomic Number 34 higher 19 higher
Symbol Se different K different
Name Selenium different Potassium different
Atomic Mass 78.97 higher 39.0983 higher
Category Reactive Nonmetals different Alkali Metals different
Period 4 same value 4 same value
Group 16 higher 1 higher
Block p-Block different s-Block different
Standard State Solid same value Solid same value
Electronegativity 2.55 higher 0.82 higher
Atomic Radius 190 lower 275 lower
Ionization Energy 9.752 higher 4.341 higher
Electron Affinity 2.021 higher 0.501 higher
Oxidation States +6, +4, -2 different +1 different
Melting Point 493.65 K (220.5 °C) higher 336.53 K (63.38 °C) higher
Boiling Point 958 K (684.85 °C) lower 1032 K (758.85 °C) lower
Density 4.809 higher 0.89 higher
Electron Configuration [Ar]4s2 3d10 4p4 different [Ar]4s1 different
Year Discovered 1817 different 1807 different

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