What Is Arsenic?

Arsenic, the thirty-third element on the periodic table, is a gray, metallic-looking metalloid. It's infamous as a poison but also valuable in modern technology.

Atomic Number: 33

Symbol: As

Atomic Mass: 74.922 u

Category: Metalloid

State at Room Temperature: Solid

Discovered By: Known since antiquity, isolated by Albertus Magnus (circa 1250)

⚛️ Atomic Structure of Arsenic

Arsenic has thirty-three protons, forty-two neutrons (in its only stable isotope, Arsenic-75), and thirty-three electrons, with five in its outer shell.

  • 🟢 Protons: 33
  • 🔴 Neutrons: 42 (Stable isotope, Arsenic-75)
  • 🟡 Electrons: 33

💡 Did you know? Arsenic-76, a radioactive isotope, is used in medical research and tracing studies!

🔬 Arsenic Properties

Arsenic is brittle, semiconducting, and sublimes (turns to gas) at 615°C (1139°F) rather than melting under standard pressure. It has a metallic sheen.

🧪 How Was Arsenic Discovered?

Arsenic compounds were known since antiquity, used in medicines and pigments. German alchemist Albertus Magnus likely isolated it around 1250 by heating arsenic trisulfide.

⚡ Uses of Arsenic

  • 💻 Semiconductors: Gallium arsenide in electronics.
  • 🌾 Pesticides: Historically in agriculture (now limited).
  • 🏭 Industry: Wood preservatives and glass production.
  • 🎨 Pigments: Green dyes in the past (e.g., Paris Green).

💡 Fun Facts About Arsenic

  • ☠️ Known as the "king of poisons" in history.
  • 🌍 Found in Earth's crust and groundwater.
  • 🔥 Burns with a blue flame, producing a garlic-like odor.
  • 📜 Used in Bronze Age alloys unknowingly.

⚠️ Safety & Precautions

Arsenic is highly toxic and carcinogenic, especially in compounds like arsenic trioxide. Avoid ingestion, inhalation, or skin contact; use protective gear when handling.

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