Question

subatomic particles ii
objectives: use the atomic number and mass number to calculate the number of protons,
neutrons, and electrons.
a. complete the table

b. for each of the following isotopes, fill in the missing information. assume all
atoms are neutral

Explanation:

Step1: Recall atomic number and mass number relationships

• Atomic number (\(Z\)) = number of protons = number of electrons (for neutral atoms).
• Mass number (\(A\)) = number of protons (\(p\)) + number of neutrons (\(n\)).

Step2: Analyze \(^{23}\text{Na}\)

• For sodium (\(\text{Na}\)), atomic number \(Z = 11\) (from periodic table).
• Mass number \(A=23\) (given in symbol \(^{23}\text{Na}\)).
• Number of protons \(p = Z=11\).
• Number of electrons \(e=p = 11\) (neutral atom).
• Number of neutrons \(n=A - Z=23 - 11 = 12\).

Step3: Analyze \(\text{K}\)

• For potassium (\(\text{K}\)), number of electrons \(e = 19\). Since it's neutral, number of protons \(p=19\) (atomic number \(Z = 19\)).
• Mass number \(A = 40\) (given).
• Number of neutrons \(n=A - Z=40 - 19 = 21\).

Step4: Analyze the element with \(p = 38\), \(e = 38\), \(n = 52\)

• Atomic number \(Z=p = 38\) (strontium, \(\text{Sr}\)).
• Mass number \(A=p + n=38+52 = 90\).

Step5: Analyze \(\text{F}\)

• For fluorine (\(\text{F}\)), atomic number \(Z = 9\) (from periodic table).
• Number of protons \(p = Z=9\).
• Number of electrons \(e=p = 9\) (neutral atom).
• Mass number \(A=p + n=9 + 10=19\).

Step6: Analyze carbon isotopes

• For carbon (\(\text{C}\)), atomic number \(Z = 6\) (from periodic table).
• Carbon - 12:
• Number of protons \(p = Z = 6\).
• Number of neutrons \(n=A - Z=12 - 6 = 6\).
• Number of electrons \(e=p = 6\).
• Carbon - 13:
• Number of protons \(p = Z = 6\).
• Number of neutrons \(n=A - Z=13 - 6 = 7\).
• Number of electrons \(e=p = 6\).
• Carbon - 14:
• Number of protons \(p = Z = 6\).
• Number of neutrons \(n=A - Z=14 - 6 = 8\).
• Number of electrons \(e=p = 6\).

Answer:

Symbol	Atomic Number	Mass Number	Number of Protons	Number of Electrons	Number of Neutrons
\(\text{K}\)	\(19\)	\(40\)	\(19\)	\(19\)	\(21\)
\(\text{Sr}\)	\(38\)	\(90\)	\(38\)	\(38\)	\(52\)
\(\text{F}\)	\(9\)	\(19\)	\(9\)	\(9\)	\(10\)

	Carbon - 12	Carbon - 13	Carbon - 14
# of neutrons	\(6\)	\(7\)	\(8\)
# of electrons	\(6\)	\(6\)	\(6\)