Meitnerium

Chaitra 05/07/2026 12:03:03 Updated 05/07/2026 12:03:03

Property	Value
Atomic Number	109
Element	Meitnerium
Symbol	Mt
Atomic Mass	[278] (most stable isotope)
Number of Neutrons	169 (Meitnerium-278)
Number of Protons	109
Number of Electrons	109
Period	7
Group	9
Phase	Solid (predicted)
Radioactive	Yes
Natural	No (synthetic element)
Metal	Yes (predicted)
Nonmetal	No
Metalloid	No
Type	Transition Metal
Atomic Radius	— (not well established)
Electronegativity	— (not well established)
First Ionization Energy	~7.8 eV (estimated)
Density	~37 g/cm³ (estimated)
Melting Point	— (not well established)
Boiling Point	— (not well established)
Number of Isotopes	No stable isotopes (Mt-278 most notable)
Discoverer	Gesellschaft für Schwerionenforschung (GSI), Germany
Year	1982
Specific Heat	— (not well established)
Number of Shells	7
Number of Valence Electrons	9