Atomic Number
51
Element 51
Antimony (Sb)
Antimony is a chemical element with symbol Sb and atomic number 51. A lustrous gray metalloid, it is found in nature mainly as the sulfide mineral stibnite.
Atomic Mass
121.76 u
Category
Metalloid
Period
5
Group
Group 15: nitrogen group
Phase
solid
Density
6.697 g/cm3
Electron Shells
2, 8, 18, 18, 5
Atomic Structure
Protons: 51. Electrons: 51. Neutrons: Varies by isotope.
Electron configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p³
Why Antimony Matters
Antimony helps connect atomic number 51, metalloid behavior, period 5 trends, and electron shell structure. Its solid phase, atomic mass of 121.76 u, and electron configuration 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p³ make it useful for comparing bonding patterns across the periodic table.
Discovery and Occurrence
Antimony was discovered Unknown. Antimony is a chemical element with symbol Sb and atomic number 51. A lustrous gray metalloid, it is found in nature mainly as the sulfide mineral stibnite.
Safety and Handling Context
Antimony 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 Antimony?
- Antimony has atomic number 51, which means a neutral atom has 51 protons and 51 electrons.
- What is the chemical symbol for Antimony?
- The chemical symbol for Antimony is Sb.
- What category is Antimony in?
- Antimony is classified as a metalloid and sits in period 5 of the periodic table.
Explore Antimony in 3D
Use the interactive table above to rotate atomic models, compare periodic trends, and move from Antimony to neighboring elements without losing your place.