Compare Elements

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

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Element comparison
Property Cs Cesium Tl Thallium
Atomic Number 55 lower 81 lower
Symbol Cs different Tl different
Name Cesium different Thallium different
Atomic Mass 132.9055 lower 204.383 lower
Category Alkali Metals different Post-transition Metals different
Period 6 same value 6 same value
Group 1 lower 13 lower
Block s-Block different p-Block different
Standard State Solid same value Solid same value
Electronegativity 0.79 lower 1.62 lower
Atomic Radius 343 higher 196 higher
Ionization Energy 3.894 lower 6.108 lower
Electron Affinity 0.472 higher 0.2 higher
Oxidation States +1 different +3, +1 different
Melting Point 301.59 K (28.44 °C) lower 577 K (303.85 °C) lower
Boiling Point 944 K (670.85 °C) lower 1746 K (1472.85 °C) lower
Density 1.93 lower 11.8 lower
Electron Configuration [Xe]6s1 different [Xe]6s2 4f14 5d10 6p1 different
Year Discovered 1860 different 1861 different

higher lower