Terbium

LANTHANIDE

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

Terbium is a chemical element with symbol Tb and atomic number 65. It is a silvery-white rare earth metal that is malleable, ductile and soft enough to be cut with a knife. Terbium is never found in nature as a free element, but it is contained in many minerals, including cerite, gadolinite, monazite, xenotime and euxenite.

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Quick Facts

Atomic Number 65

Period 6

Group 11

Phase Solid

Appearance silvery white

About Lanthanides

Lanthanides are shiny metallic elements with atomic numbers 57–71. They are often called 'rare-earth elements' and are used in magnets and lasers.

History

Discovered By Carl Gustaf Mosander

Named By Unknown

Physical Properties

Atomic Mass 158.925352

Density 8.23 g/L

Molar Heat 28.91 J/(mol·K)

Phase Transition (Melting & Boiling Points)

Terbium melts at 1629 K and boils at 3396 K.

Atomic Properties

Electron Config [Xe] 4f9 6s2

Electronegativity 1.1

Electron Affinity 112.4 kJ/mol

Ionization Energy 565.8 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

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.