Element 33: Arsenic

Have you heard about the element Arsenic? The element that serves both harmful and beneficial effects on human life. It is a naturally occurring element that can be very toxic to humans if exposure limits are too high. It is found in soil, water, and even foods, which may cause serious health risks such as cancer and damage to organs. 

This article provides you with an understanding of what arsenic is, its impacts on our health, and also the applications of Arsenic.

Table of Contents

• Must Know Facts About Arsenic
• What is Arsenic
• Properties of Arsenic
• Chemical Properties of Arsenic
• Safety Note to Handle Arsenic

Must Know Facts About Arsenic!

 

Interestingly!! Arsenic is usually present in all its forms in minute quantities in soil, water, and air. Arsenic exists both in elemental form and as chemical compounds. Most such compounds are toxic to living organisms.

Next, Arsenic shows a trend specifically which makes it easy to identify.

Properties of Arsenic

Arsenic displays remarkable chemical properties as a result of its placement in the periodic table. The following are some of its major chemical properties:

 

 

Chemical Properties of Arsenic

➔ Allotropic Nature:

• Exists in grey (stable), yellow (reactive), and black (unstable) forms.
• Grey is metallic and a poor conductor; yellow is produced by cooling vapours.
  
  

➔ Reactivity:

• Inert at room temperature in dry air.
• Burns with a blue flame, releasing garlic-like odour due to arsenic trioxide (As₂O₃).
  
  

➔ Oxidation States:

• Common states: -3, +3, +5.
• Forms highly toxic arsine gas (AsH₃) and acids like H₃AsO₃ and H₃AsO₄.

Zn3As2+6HCl→3ZnCl2+2AsH3↑

➔ Reactions with Other Elements:

• Combines with halogens (e.g., AsCl₃) and metals (forms arsenides).

2As+3Cl2→2AsCl3

➔ Solubility:

• Elemental arsenic is water-insoluble.
• Most compounds (especially oxides and acids) are soluble and toxic.

Also, you can check other elements: Argon, Actinum

Uses of Arsenic

• It is used in CCA to protect wood; now banned/restricted due to toxicity.

• It is formerly used in agriculture; now limited by regulations.

• Have you noticed that Gallium arsenide (GaAs) is used in solar cells, LEDs, and high-speed electronics?

• It is used to decolour glass and in certain enamels/ceramics.

• It strengthens lead alloys; used in batteries and bullets.

• When treating syphilis and psoriasis, still used in some cancer treatments (e.g., APL).

• Used in Paris Green and Scheele’s Green; banned due to toxicity.

Safety Note to Handle Arsenic 

• Inorganic arsenic compounds are extremely toxic.

• Long-term exposure can lead to skin issues, respiratory problems, and cancer.

• Requires strict handling and environmental controls.

Learning about arsenic and how it can affect your health is necessary to protect your health and take steps to lower your exposure to it. Knowing where arsenic naturally occurs and how it can enter your body means you can now use this knowledge in the real world to make decisions to limit your exposure.