What Is Polonium?
With atomic number 84 and chemical symbol Po, Polonium sits among the post-transition metals just right of the main transition block.
A highly radioactive element discovered by Marie Curie. Named after her homeland Poland.
As a post-transition metal in Period 6 and Group 16 (Oxygen Group / Chalcogens), polonium's placement on the table reflects its electron configuration of [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁴, which governs its bonding behavior and the type of compounds it typically forms.
Position on the Periodic Table
Polonium is located in Period 6, an unusually long row that includes the entire lanthanide series.
Within that row, polonium sits in Group 16 (Oxygen Group / Chalcogens), alongside elements that share a similar number of valence electrons and, by extension, similar chemical behavior.
This position is not arbitrary — the periodic table was deliberately organized so that an element's row and column reveal its expected reactivity, bonding pattern, and physical state at a glance.
Physical & Chemical Properties
Polonium has an atomic mass of (209) u and a density of 9.32 g/cm³. Its melting point is 254°C and its boiling point is 962°C.
Polonium is generally softer and lower-melting than the transition metals positioned to its left on the periodic table.
Electron Configuration Explained
Polonium's electron configuration is [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁴, describing how its electrons are distributed across shells and subshells around the nucleus.
Reading the configuration in order shows electrons filling shells of increasing energy, following the standard Aufbau principle that explains how atomic structure builds up across the periodic table.
The outermost (valence) electrons shown in this configuration are what ultimately determine polonium's chemical reactivity and the type of bonds it forms with other elements.
History & Discovery
Polonium was formally discovered in 1898, Marie Curie, identified through the careful isolation and analytical techniques typical of that era's chemical research.
Many elements from this period were anticipated by Dmitri Mendeleev's periodic table, which successfully predicted gaps corresponding to undiscovered elements well before laboratory instruments existed to confirm them directly.
What Is Polonium Used For?
Polonium's specific properties make it useful in several applications, including:
- Anti-static devices
- Nuclear batteries
- Neutron sources
- Research
- Historical assassination
These uses reflect polonium's underlying classification as a post-transition metal, since the same properties that define its category in chemistry also determine where it becomes practically useful.
Fun Facts About Polonium
- Polonium-210 was used to assassinate Alexander Litvinenko in London in 2006.
- Polonium is element number 84 on the periodic table, in Period 6 and Group 16.
- Its standard atomic mass is (209) u, calculated from the natural abundance of its isotopes.
Frequently Asked Questions
What is Polonium's atomic number?
Polonium has atomic number 84.
What is Polonium's chemical symbol?
Polonium's symbol is Po.
What group and period is Polonium in?
Polonium is in Period 6, Group 16 (Oxygen Group / Chalcogens).
What is Polonium's atomic mass?
Polonium's standard atomic mass is (209) u.