What Is Technetium?
Technetium is a chemical element with the symbol Tc and atomic number 43, found within the transition metal block of the periodic table.
The first artificially produced element. All its isotopes are radioactive.
As a transition metal in Period 5 and Group 7 (Transition Metals), technetium's placement on the table reflects its electron configuration of [Kr] 4d⁵ 5s², which governs its bonding behavior and the type of compounds it typically forms.
Position on the Periodic Table
Technetium is located in Period 5, which continues the transition metal pattern seen in Period 4 but one principal shell further out.
Within that row, technetium sits in Group 7 (Transition Metals), 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
Technetium has an atomic mass of (98) u and a density of 11.5 g/cm³. Its melting point is 2157°C and its boiling point is 4265°C.
As a transition metal, technetium conducts electricity and heat well, and its atoms pack into a metallic crystal lattice held together by shared, delocalized electrons.
Electron Configuration Explained
Technetium's electron configuration is [Kr] 4d⁵ 5s², 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 technetium's chemical reactivity and the type of bonds it forms with other elements.
History & Discovery
Technetium was formally discovered in 1937, Perrier & Segrè, 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 Technetium Used For?
Technetium's specific properties make it useful in several applications, including:
- Medical imaging (bone scans)
- Cancer detection
- Industrial radiography
- Research
- Corrosion inhibitor
These uses reflect technetium's underlying classification as a transition metal, since the same properties that define its category in chemistry also determine where it becomes practically useful.
Fun Facts About Technetium
- Technetium was the first element to be artificially produced in a laboratory.
- Technetium is element number 43 on the periodic table, in Period 5 and Group 7.
- Its standard atomic mass is (98) u, calculated from the natural abundance of its isotopes.
Frequently Asked Questions
What is Technetium's atomic number?
Technetium has atomic number 43.
What is Technetium's chemical symbol?
Technetium's symbol is Tc.
What group and period is Technetium in?
Technetium is in Period 5, Group 7 (Transition Metals).
What is Technetium's atomic mass?
Technetium's standard atomic mass is (98) u.