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α-particle consists of

Asked in NEET (National) 2019 · Nature of alpha, beta and gamma radiation

• (1) 2 electrons, 2 protons and 2 neutrons
• (2) 2 electrons and 4 protons only
• (3) 2 protons only
• (4) 2 protons and 2 neutrons only

Step-by-step solution

Why the other options are wrong

• (1) comes from adds electrons to what is a bare nucleus; an α-particle is doubly ionised helium and carries none.
• (2) comes from gives helium four protons, which would make its atomic number 4 instead of 2.
• (3) comes from counts only the charge and leaves out the two neutrons, giving a mass number of 2 instead of 4.

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