Sb Antimony

Quick answerAntimony (Sb) is a metalloid with atomic number 51 and an atomic mass of 121.76 (2023), in group 15, period 5. It has been known since ancient times. It is used for flame retardants and lead-acid batteries. Its electron configuration is [Kr] 4d10 5s2 5p3.

Antimony has been known since antiquity, and today it flame-proofs fabrics and plastics and hardens lead in batteries.

Key facts

Symbol	Sb
Atomic number	51
Atomic mass	121.76 (IUPAC standard atomic weight, 2023)
Category	metalloid
Group	15
Period	5
Block	p-block
Electron configuration	[Kr] 4d10 5s2 5p3
Discovered	Known since ancient times
Uses	flame retardants, lead-acid batteries, alloys, semiconductors, ceramics

Quick quiz

Three questions from the facts on this page. No sign-up, no score is saved.

1. What is the chemical symbol of Antimony?

Sb B Ge Si

2. What is the atomic number of Antimony?

52 50 51 53

3. Which category does Antimony belong to?

noble gas halogen metalloid alkali metal

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Keep exploring

• Periodic table — all 118 elements
• Boron (B) — another metalloid, atomic number 5
• Silicon (Si) — another metalloid, atomic number 14
• Germanium (Ge) — another metalloid, atomic number 32
• Arsenic (As) — another metalloid, atomic number 33
• Tellurium (Te) — another metalloid, atomic number 52

Sources & last updated

• CIAAW — Standard Atomic Weights
• PubChem Periodic Table

Last updated: 2026-11-12. Figures are shown with their year; where sources disagree, the value is left out rather than estimated.