1) Which of the following is the most massive part of an atom?

A) area outside the nucleus

B) protons

C) neutrons

D) nucleus

2) Which of the following is the most complete list of the particles that are located within the nucleus of an atom?

A) protons only

B) protons and neutrons

C) neutrons and electrons

D) protons and electrons

1. D - nucleus

2. B - protons and neutrons

For 1: The correct answer is Option D.

For 2: The correct answer is Option B.

Explanation:

For 1:

Nucleus is defined as the positively charged center of the atom consisting of protons and neutrons. All the mass of atom is contained in the nucleus.

Electrons are the sub-atomic particles which surround the nucleus of an atom and are present in orbits.

Mass of protons and neutrons are more than the mass of electrons.

Hence, the most massive part of an atom is nucleus.

Therefore, the correct answer is Option D.

For 2:

There are 3 subatomic particles present in an atom. They are: protons, electrons and neutrons.

Protons: They carry positive charger and are found in nucleus. Electrons: They carry negative charge and are found around the nucleus. Neutrons: They dos not carry any charge and are found in nucleus.

Hence, the correct answer is Option B.