Atomic Number
71
Element 71
Lutetium (Lu)
Lutetium is a chemical element with symbol Lu and atomic number 71. It is a silvery white metal, which resists corrosion in dry air, but not in moist air.
Atomic Mass
174.97 u
Category
Lanthanide
Period
6
Group
Lanthanide series
Phase
solid
Density
9.84 g/cm3
Electron Shells
2, 8, 18, 32, 9, 2
Atomic Structure
Protons: 71. Electrons: 71. Neutrons: Varies by isotope.
Electron configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹
Why Lutetium Matters
Lutetium helps connect atomic number 71, lanthanide behavior, period 6 trends, and electron shell structure. Its solid phase, atomic mass of 174.97 u, and electron configuration 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹ make it useful for comparing bonding patterns across the periodic table.
Discovery and Occurrence
Lutetium was discovered 1907 by Georges Urbain, Carl Auer von Welsbach. Lutetium is a chemical element with symbol Lu and atomic number 71. It is a silvery white metal, which resists corrosion in dry air, but not in moist air.
Safety and Handling Context
Lutetium is presented here for learning and comparison. Pure elements and laboratory compounds can have hazards that depend on dose, form, and setting.
Related Elements
Frequently Asked Questions
- What is the atomic number of Lutetium?
- Lutetium has atomic number 71, which means a neutral atom has 71 protons and 71 electrons.
- What is the chemical symbol for Lutetium?
- The chemical symbol for Lutetium is Lu.
- What category is Lutetium in?
- Lutetium is classified as a lanthanide and sits in period 6 of the periodic table.
Explore Lutetium in 3D
Use the interactive table above to rotate atomic models, compare periodic trends, and move from Lutetium to neighboring elements without losing your place.