Atomic Number
43
Element 43
Technetium (Tc)
Technetium is a chemical element with symbol Tc and atomic number 43. It is the lightest element whose isotopes are all radioactive, none of which are stable.
Atomic Mass
98 u
Category
Transition Metal
Period
5
Group
Group 7: manganese group
Phase
solid
Density
11.5 g/cm3
Electron Shells
2, 8, 18, 13, 2
Atomic Structure
Protons: 43. Electrons: 43. Neutrons: Varies by isotope.
Electron configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d⁵
Why Technetium Matters
Technetium helps connect atomic number 43, transition metal behavior, period 5 trends, and electron shell structure. Its solid phase, atomic mass of 98 u, and electron configuration 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d⁵ make it useful for comparing bonding patterns across the periodic table.
Discovery and Occurrence
Technetium was discovered 1937 by Carlo Perrier, Emilio Segrè. Technetium is a chemical element with symbol Tc and atomic number 43. It is the lightest element whose isotopes are all radioactive, none of which are stable.
Safety and Handling Context
Technetium has radioactive isotopes or is commonly discussed with radioactive materials. Use this page as an educational reference; real samples require qualified supervision and controlled handling.
Related Elements
Frequently Asked Questions
- What is the atomic number of Technetium?
- Technetium has atomic number 43, which means a neutral atom has 43 protons and 43 electrons.
- What is the chemical symbol for Technetium?
- The chemical symbol for Technetium is Tc.
- What category is Technetium in?
- Technetium is classified as a transition metal and sits in period 5 of the periodic table.
Explore Technetium in 3D
Use the interactive table above to rotate atomic models, compare periodic trends, and move from Technetium to neighboring elements without losing your place.