MCQ Detailed View

A cation is a type of ion that carries a positive charge. The term “cation” comes from the Greek word kata (meaning “down”), and it refers to ions that move toward the cathode (negative electrode) during electrolysis.

Cations are formed when an atom loses one or more electrons. Since electrons are negatively charged, the loss of electrons leaves the atom with more protons (positive charges) than electrons (negative charges). As a result, the overall charge becomes positive.

For example:

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  Sodium atom (Na) normally has 11 protons and 11 electrons, making it neutral. When it loses 1 electron, it becomes Na⁺ (a cation) with a +1 charge.

  
  


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  Calcium atom (Ca) has 20 protons and 20 electrons. When it loses 2 electrons, it becomes Ca²⁺ (a cation) with a +2 charge.

  
  

Cations are commonly formed by metals because metals have a low ionization energy and tend to lose electrons easily. This is why metallic elements often appear as positively charged ions in chemical compounds and ionic lattices.

Properties of cations:

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  They are smaller than their parent atoms because losing electrons reduces electron-electron repulsion and allows the nucleus to pull remaining electrons closer.

  
  


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  They are attracted to negatively charged species (anions) to form ionic compounds such as NaCl (sodium chloride).

  
  


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  They move toward the cathode during electrolysis.

  
  

Why not the other options?

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  -ve (option 2): Negative charge belongs to anions, not cations.

  
  


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  Neutral (option 3): Neutral atoms have equal protons and electrons, but cations always have excess protons.

  
  


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  None (option 4): Incorrect, because cations are never charge-less.

  
  

Key fact:
Cations play a vital role in biological and chemical systems. For instance, Na⁺, K⁺, Ca²⁺, and Mg²⁺ are essential cations in the human body, responsible for nerve impulses, muscle contraction, and cellular functions.