The particle that makes the nucleus positive

The idea

The positive charge of the nucleus comes from protons, which are much heavier than electrons and carry a charge equal and opposite to that of an electron.

A positive centre

Rutherford showed that the nucleus carries positive charge. Something inside the nucleus must be carrying it.

Which particles give the nucleus its positive charge?

• Protons
• Electrons
• Cathode rays

Proton or electron?

Sort each fact into the right group.

The positive particle

The nucleus is positive because it contains protons. A proton and an electron have charges of the same size but opposite kinds.

The positive charge of the nucleus comes from protons. Protons are much heavier than electrons and carry a charge equal and opposite to that of an electron.

Notes

Protons give the nucleus its positive charge. They are much heavier than electrons, with a charge equal and opposite to an electron's.

Check yourself

Which particle gives the nucleus its positive charge?

Compared with an electron, a proton is …

How does the charge of a proton compare with the charge of an electron?

Who discovered and named the proton?

• Electron. Electrons carry negative charge and revolve around the nucleus.
• Proton — correct. Yes!
• Cathode ray. Cathode rays are streams of electrons, which are negatively charged.
• much lighter. Protons are much heavier than electrons.
• about the same mass. The book says protons are much heavier than electrons.
• much heavier — correct. Yes!
• Equal in size and opposite in kind — correct. Yes!
• Equal in size and the same in kind. An electron is negative and a proton is positive, so they are opposite.
• Twice as large and opposite. The charges are equal in size.
• Thomson. Thomson discovered the electron.
• Rutherford — correct. Yes!
• Chadwick. Chadwick discovered the neutron in 1932.