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43 Tc Technetium 98

Technetium

TRANSITION METAL
Bohr Model: Electrons arranged in energy shells around the nucleus.

Technetium (/tɛkˈniːʃiəm/) is a chemical element with symbol Tc and atomic number 43. It is the element with the lowest atomic number in the periodic table that has no stable isotopes:every form of it is radioactive. Nearly all technetium is produced synthetically, and only minute amounts are found in nature.

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Quick Facts

Atomic Number 43
Period 5
Group 7
Phase Solid
Appearance shiny gray metal
About Transition Metals

Transition metals are elements with partially filled d-orbitals. They are hard, have high melting points, and often form colored compounds.

History

Discovered By Emilio Segrè
Named By Unknown

Physical Properties

Atomic Mass 98
Density 11 g/L
Molar Heat 24.27 J/(mol·K)
Phase Transition (Melting & Boiling Points)

Technetium melts at 2430 K and boils at 4538 K.

Atomic Properties

Electron Config [Kr] 4d5 5s2
Electronegativity 1.9
Electron Affinity 53 kJ/mol
Ionization Energy 702 kJ/mol
Orbital Filling Diagram
This diagram visualizes electron configuration according to the Aufbau principle and Hund's rule. Boxes represent orbitals (s, p, d, f), while arrows indicate electrons with spin up or down. Electrons fill lower energy levels first and occupy orbitals singly before pairing.

Photograph

Image of Technetium Source: Wikipedia

External Resources

Wikipedia PubChem Royal Society of Chemistry Periodic Videos (YouTube)

Study Guide

Atomic Number

The number of protons in the nucleus, which defines the element.

Atomic Mass

The average mass of an atom, including protons and neutrons.

Electronegativity

A measure of how strongly an atom attracts electrons in a bond.

Ionization Energy

The energy required to remove an electron from an atom.

Electron Config

The arrangement of electrons in the atom's energy shells.