Compare Elements

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

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Element comparison
Property Sm Samarium Pm Promethium
Atomic Number 62 higher 61 higher
Symbol Sm different Pm different
Name Samarium different Promethium different
Atomic Mass 150.4 higher 144.9128 higher
Category Lanthanides same value Lanthanides same value
Period 6 same value 6 same value
Group 3 same value 3 same value
Block f-Block same value f-Block same value
Standard State Solid same value Solid same value
Electronegativity 1.17 no data — no data
Atomic Radius 229 lower 236 lower
Ionization Energy 5.644 higher 5.55 higher
Electron Affinity — no data — no data
Oxidation States +3, +2 different +3 different
Melting Point 1347 K (1073.85 °C) higher 1315 K (1041.85 °C) higher
Boiling Point 2067 K (1793.85 °C) lower 3273 K (2999.85 °C) lower
Density 7.52 higher 7.26 higher
Electron Configuration [Xe]6s2 4f6 different [Xe]6s2 4f5 different
Year Discovered 1879 different 1945 different

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