Question

Who proposed 1st model of an atom ?

• A. Eugene Goldstein
• B. Crooks
• C. J.J. Thomson
• D. Neils Bohr

Answer 1

The correct option is C

J.J. Thomson

Explanation for the correct answer

Option C

• J.J. Thomson proposed the first model of an atom.
• He has proposed that an atom consists of a sphere of positive charge with negatively charged electrons embedded in it.
• He has also stated that the positive and negative charges in an atom are equal in magnitude due to which an atom as a whole is electrically neutral.
• J.J. Thomson's model of an atom is known as the watermelon model or plum pudding model.

Explanation for the incorrect answers

Option A

• Eugene Goldstein discovered positive particles by using a tube filled with Hydrogen gas.
• The resulted in positive particle had a charge equal to and opposite to the electron.
• The positive particle was named the proton.

Option B

• Crookes tube is an experimental electrical discharge tube with partial vacuum discovered by scientist William Crookes.

Option D

• Neils Bohr proposed the structure of an atom.
• He stated that negatively charged electrons are revolving around the positively charged nucleus in a definite circular path known as orbit or shell
• Each orbit is associated with a definite amount of energy.
• Electrons can gain or lose energy by moving from one orbit to another.
• So the energy of an electron that remains in a particular orbit is always constant.

Conclusion: Hence option C is correct.