Question

particle a has very little mass in comparison to particle b. both particles are in the same atom. which is the best conclusion about particles a and b?
they have the same charge.
they are located in the nucleus together.
particle a has a positive charge, and particle b is neutral.
particle a orbits the nucleus, and particle b is located in the nucleus.

Explanation:

In an atom, electrons have very little mass compared to protons and neutrons (which are in the nucleus). Electrons orbit the nucleus, while protons and neutrons (with more mass) are in the nucleus. So Particle A (low mass, likely electron) orbits the nucleus, and Particle B (higher mass, likely proton/neutron) is in the nucleus. Let's analyze options:

• "They have the same charge": Electrons are negative, protons positive, neutrons neutral – not same charge. Eliminate.
• "They are located in the nucleus together": Electrons don't stay in nucleus. Eliminate.
• "Particle A has a positive charge, and Particle B is neutral": Electrons are negative, so A can't be positive. Eliminate.
• "Particle A orbits the nucleus, and Particle B is located in the nucleus": Matches electron (A) and proton/neutron (B) behavior.

Answer:

Particle A orbits the nucleus, and Particle B is located in the nucleus.