Which particle has a negative charge and is much lighter than protons and neutrons?

Which particle has a negative charge and is much lighter than protons and neutrons?

• A. Proton
• B. Neutron
• C. Electron
• D. Positron

Answer: (C)

Understanding the charges and masses of subatomic particles helps here. Only the electron carries a negative electrical charge. Protons have a positive charge, neutrons have no charge, and a positron is the positively charged partner of the electron (it has the same tiny mass as an electron). Additionally, electrons are much lighter than protons and neutrons—about 1/1836 of a proton’s mass—so they’re the lightweight particle among the options. So the particle described is the electron.

Understanding the charges and masses of subatomic particles helps here. Only the electron carries a negative electrical charge. Protons have a positive charge, neutrons have no charge, and a positron is the positively charged partner of the electron (it has the same tiny mass as an electron). Additionally, electrons are much lighter than protons and neutrons—about 1/1836 of a proton’s mass—so they’re the lightweight particle among the options. So the particle described is the electron.