Question

select the correct answer in each row.
atomic number mass number atomic mass
isotopes are included
number of protons in the nucleus of an atom
quantity of matter in an atom of an element
a whole number, equal to the sum of protons and neutrons

Explanation:

To solve this, we analyze each row by recalling the definitions of atomic number, mass number, and atomic mass:

Row 1: Isotopes are included

• Atomic Number: Same for isotopes (same element, same protons).
• Mass Number: Differs for isotopes (different neutrons).
• Atomic Mass: Accounts for all isotopes (weighted average of isotopic masses).

Thus, Atomic Mass includes isotopes.

Row 2: Number of protons in the nucleus of an atom

By definition, the Atomic Number is the number of protons in an atom’s nucleus.

Row 3: Quantity of matter in an atom of an element

Atomic Mass (or atomic weight) measures the mass (quantity of matter) of an atom, accounting for protons, neutrons, and electrons (with most mass from nucleus).

Row 4: A whole number, equal to the sum of protons and neutrons

The Mass Number is defined as \( \text{Mass Number} = \text{protons} + \text{neutrons} \) (a whole number, unlike atomic mass which is a decimal).

Final Answers (check the correct column for each row):

1. Isotopes are included: Atomic Mass (check the “Atomic Mass” column).
2. Number of protons in the nucleus of an atom: Atomic Number (check the “Atomic Number” column).
3. Quantity of matter in an atom of an element: Atomic Mass (check the “Atomic Mass” column).
4. A whole number, equal to the sum of protons and neutrons: Mass Number (check the “Mass Number” column).

Answer:

To solve this, we analyze each row by recalling the definitions of atomic number, mass number, and atomic mass:

Row 1: Isotopes are included

• Atomic Number: Same for isotopes (same element, same protons).
• Mass Number: Differs for isotopes (different neutrons).
• Atomic Mass: Accounts for all isotopes (weighted average of isotopic masses).

Thus, Atomic Mass includes isotopes.

Row 2: Number of protons in the nucleus of an atom

By definition, the Atomic Number is the number of protons in an atom’s nucleus.

Row 3: Quantity of matter in an atom of an element

Atomic Mass (or atomic weight) measures the mass (quantity of matter) of an atom, accounting for protons, neutrons, and electrons (with most mass from nucleus).

Row 4: A whole number, equal to the sum of protons and neutrons

The Mass Number is defined as \( \text{Mass Number} = \text{protons} + \text{neutrons} \) (a whole number, unlike atomic mass which is a decimal).

Final Answers (check the correct column for each row):

1. Isotopes are included: Atomic Mass (check the “Atomic Mass” column).
2. Number of protons in the nucleus of an atom: Atomic Number (check the “Atomic Number” column).
3. Quantity of matter in an atom of an element: Atomic Mass (check the “Atomic Mass” column).
4. A whole number, equal to the sum of protons and neutrons: Mass Number (check the “Mass Number” column).