​The atomic number of oxygen is _______.​

Correct option is C

The correct answer is (C) 8.

• The atomic number or proton number of any chemical element is the number of protons found in the nucleus of every atom of that element.
  
• It is denoted by symbol Z.
• It is identical to the charge number of the nucleus.
  
• For oxygen, there are 8 protons present in the nucleus.
  
• So, Z=8

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