Question

1. refer to model 1. what subatomic particles do the following symbols represent in the atomic diagrams?
2. complete the table in model 1 by counting the protons and neutrons in each atomic diagram. divide the work evenly among group members.
3. find the three elements shown in model 1 on your periodic table.

a. what whole number shown in model 1 for each element is also found in the periodic table for that element?
hydrogen - carbon - magnesium -
b. the whole number in each box of the periodic table is the atomic number of the element. what does the atomic number of an element represent?
c. refer to the isotope symbols in model 1. relative to the atomic symbol (h, c, or mg), where is the atomic number located in the isotope symbol?

1. refer to your periodic table.

a. how many protons are in all chlorine (cl) atoms?
b. a student says “i think that some chlorine atoms have 16 protons.” explain why this student is not correct.

1. refer again to model 1. in the isotope symbol of each atom, there is a superscripted (raised) number. this number is also used in the name of the atom (i.e., carbon - 12). it is called the mass number.

a. how is the mass number determined?
b. why is this number called a “mass” number?
c. which corner of the isotope symbol contains the mass number?
d. how is the mass number of an isotope expressed in the name of an atom?

Explanation:

Step1: Identify sub - atomic particles

The symbol “−” represents an electron, the “+” represents a proton, and the “○” represents a neutron.

Step2: Answer 3a

For hydrogen, the whole number is 1; for carbon, it is 6; for magnesium, it is 12. These numbers match the atomic numbers on the periodic table.

Step3: Answer 3b

The atomic number of an element represents the number of protons in the nucleus of an atom of that element.

Step4: Answer 3c

In the isotope symbol, the atomic number is located as a sub - script to the left of the atomic symbol.

Step5: Answer 4a

All chlorine (Cl) atoms have 17 protons. This is because the atomic number of chlorine is 17, and the atomic number is equal to the number of protons.

Step6: Answer 4b

The student is not correct because the number of protons defines the element. Chlorine has an atomic number of 17, so all chlorine atoms must have 17 protons. If an atom has 16 protons, it is sulfur.

Step7: Answer 5a

The mass number is determined by adding the number of protons and neutrons in the nucleus of an atom.

Step8: Answer 5b

It is called a “mass” number because it is approximately equal to the mass of the atom in atomic mass units (amu), since protons and neutrons each have a mass of approximately 1 amu.

Step9: Answer 5c

The mass number is located as a super - script to the left of the atomic symbol in the isotope symbol.

Step10: Answer 5d

The mass number of an isotope is expressed as a number after a hyphen in the name of an atom (e.g., carbon - 12), where the number is the sum of protons and neutrons.

Answer:

1. “−” is an electron, “+” is a proton, “○” is a neutron.
2. (No table provided to complete, so no specific answer given here)
3. a. Hydrogen: 1, Carbon: 6, Magnesium: 12. b. The number of protons in the nucleus of an atom of that element. c. As a sub - script to the left of the atomic symbol.
4. a. 17. b. The number of protons defines the element. Chlorine has an atomic number of 17, so all chlorine atoms must have 17 protons. If an atom has 16 protons, it is sulfur.
5. a. By adding the number of protons and neutrons in the nucleus of an atom. b. Because it is approximately equal to the mass of the atom in atomic mass units (amu). c. As a super - script to the left of the atomic symbol. d. As a number after a hyphen in the name of an atom.