Question

ntinued)organize the information on atomic mass to complete the outline.atomic massa. nucleus of atom1. 2. 3.

Explanation:

The nucleus of an atom contains the subatomic particles that contribute nearly all of an atom's mass. These are protons, neutrons, and the key fact that electrons (outside the nucleus) contribute negligible mass.

1. Protons: Positively charged particles with a mass of ~1 atomic mass unit (amu), located in the nucleus, and their count defines the element.
2. Neutrons: Neutral particles with a mass of ~1 atomic mass unit (amu), located in the nucleus, and their count varies for isotopes of an element.
3. Contains 99.9% of atom's total mass: The combined mass of protons and neutrons in the nucleus makes up almost all of an atom's mass, as electrons have an extremely small mass (~1/1836 amu) that is usually ignored for atomic mass calculations.

Answer:

1. Protons (positively charged, ~1 amu mass)
2. Neutrons (neutral, ~1 amu mass)
3. Accounts for 99.9% of total atomic mass