Technetium (symbol Tc, atomic number 43) is the lightest element with no stable isotope, vital to medical imaging. It is classified as a transition metal and sits in group 7, period 5 of the periodic table.
Overview
Technetium is the chemical element with atomic number 43 and the symbol Tc. With a standard atomic weight of [98], it is a transition metal. In the periodic table it occupies group 7 and period 5, and under standard conditions it is normally a solid. Technetium is the lightest element with no stable isotope, vital to medical imaging.
Atomic structure
An atom of Technetium has 43 protons in its nucleus and, when neutral, 43 electrons arranged in the configuration [Kr] 4d5 5s2. Technetium has no stable isotope; the value [98] refers to the mass number of its most stable or most commonly produced isotope.
Discovery and place in the table
Technetium was discovered in 1937 by Emilio Segrè, Carlo Perrier. It follows Molybdenum (Mo) and precedes Ruthenium (Ru) in order of atomic number.
| Atomic number | 43 |
|---|---|
| Symbol | Tc |
| Atomic mass | [98] |
| Category | Transition metal |
| Group | 7 |
| Period | 5 |
| Electron configuration | [Kr] 4d5 5s2 |
| Phase at STP | Solid |
| Discovered | 1937 (Emilio Segrè, Carlo Perrier) |