Elements that have the same number of protons but a different number of neutrons are called what?

In chemistry, the term isotopes refers to atoms of a single element that have the same atomic number (number of protons) but differ in the number of neutrons. This difference in neutron number results in different mass numbers, although the atoms exhibit almost identical chemical behavior because chemical properties are primarily determined by the number of protons and electrons.

For example, carbon has three naturally occurring isotopes:

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  Carbon-12 (¹²C): 6 protons, 6 neutrons

  
  


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  Carbon-13 (¹³C): 6 protons, 7 neutrons

  
  


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  Carbon-14 (¹⁴C): 6 protons, 8 neutrons

  
  

All three isotopes are chemically identical, reacting in the same way with other elements, but they differ in atomic mass. Some isotopes, like Carbon-14, are radioactive and used in radiocarbon dating, while stable isotopes like Carbon-12 and Carbon-13 are widely used in industrial and scientific applications.

Key Points About Isotopes:

1. 
   

   Same element: Must have the same number of protons.

   
   


2. 
   

   Different mass number: Number of neutrons varies.

   
   


3. 
   

   Chemical similarity: Same chemical properties due to identical electron configurations.

   
   


4. 
   

   Physical differences: Different densities, mass, and sometimes radioactive properties.

   
   

Applications of Isotopes:

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  Medicine: Radioisotopes used in diagnostics and treatment.

  
  


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  Archaeology: Carbon-14 dating for ancient artifacts.

  
  


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  Industry: Tracer studies to monitor chemical processes.

  
  

Conclusion:
Atoms with the same number of protons but a different number of neutrons are called isotopes. They are fundamental to understanding atomic structure, nuclear chemistry, and applications in science and technology.