Atomic Number
49
Element 49
Indium (In)
Indium is a chemical element with symbol In and atomic number 49. It is a post-transition metal that makes up 0.21 parts per million of the Earth's crust.
Atomic Mass
114.82 u
Category
Post-Transition Metal
Period
5
Group
Group 13: boron group
Phase
solid
Density
7.31 g/cm3
Electron Shells
2, 8, 18, 18, 3
Atomic Structure
Protons: 49. Electrons: 49. Neutrons: Varies by isotope.
Electron configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p¹
Why Indium Matters
Indium helps connect atomic number 49, post-transition metal behavior, period 5 trends, and electron shell structure. Its solid phase, atomic mass of 114.82 u, and electron configuration 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p¹ make it useful for comparing bonding patterns across the periodic table.
Discovery and Occurrence
Indium was discovered 1863 by Ferdinand Reich, Hieronymous Theodor Richter. Indium is a chemical element with symbol In and atomic number 49. It is a post-transition metal that makes up 0.21 parts per million of the Earth's crust.
Safety and Handling Context
Indium 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 Indium?
- Indium has atomic number 49, which means a neutral atom has 49 protons and 49 electrons.
- What is the chemical symbol for Indium?
- The chemical symbol for Indium is In.
- What category is Indium in?
- Indium is classified as a post-transition metal and sits in period 5 of the periodic table.
Explore Indium in 3D
Use the interactive table above to rotate atomic models, compare periodic trends, and move from Indium to neighboring elements without losing your place.