Question

which subatomic particles contribute the most to the mass of an atom? 1 point protons, neutrons, electrons protons only protons and electrons protons and neutrons what is the mass number of this atom? 1 point lithium 1 3 4 7

Explanation:

• First question: Protons and neutrons are located in the nucleus of an atom. Electrons have a negligible mass compared to protons and neutrons. So protons and neutrons contribute the most to the mass of an atom.
• Second question: The mass number of an atom is the sum of the number of protons and neutrons. In the lithium atom diagram, there are 3 protons (blue + charged particles) and 4 neutrons (grey 0 - charged particles). So mass number \(=3 + 4=7\).

Answer:

• First question: Protons and Neutrons
• Second question: 7