Question

2.1 the nature of matter

1. in the atom, which particles are in constant motion around the nucleus?

a. protons
b. protons and neutrons
c. neutrons
d. electrons

1. how do the properties of sodium chloride (nacl) compare with the properties of its component elements, sodium (na) and chlorine (cl)?
2. how do the isotopes of an element differ?
3. describe the electric charges of the three main subatomic particles.
4. when might van der waals forces be strong enough to hold two molecules together?
5. how does the behavior of an electron change when it forms a covalent bond?

Explanation:

1. In an atom, electrons are in constant motion around the nucleus. Protons and neutrons are in the nucleus.
2. Sodium chloride (NaCl) is a compound with properties different from sodium (Na) and chlorine (Cl). Sodium is a reactive metal and chlorine is a toxic gas, while NaCl is a common salt.
3. Isotopes of an element have the same number of protons but different numbers of neutrons, so they have different atomic masses.
4. Protons have a positive charge, electrons have a negative charge, and neutrons have no charge.
5. Van der Waals forces can be strong enough to hold two molecules together when the molecules are very close and have temporary dipoles.
6. When an electron forms a covalent bond, it is shared between two atoms instead of being associated with just one atom.

Answer:

1. d. electrons
2. Sodium chloride has different properties from sodium and chlorine. Sodium is a reactive metal, chlorine is a toxic gas, and NaCl is a common - salt.
3. Isotopes have the same number of protons but different numbers of neutrons and thus different atomic masses.
4. Protons have a positive charge, electrons have a negative charge, neutrons have no charge.
5. When the molecules are very close and have temporary dipoles.
6. It is shared between two atoms instead of being associated with just one atom.