Question

part a
an isotope represented as s - 34:
○ must have exactly 18 electrons.
○ is an isotope of sodium.
○ has 34 protons.
○ contains exactly 18 neutrons.

Explanation:

• For an isotope S - 34:
• Sulfur (S) has an atomic number of 16. In a neutral atom, the number of electrons equals the number of protons. So, the number of electrons is 16 (not 18), and the number of protons is 16 (not 34).
• Isotopes are of the same element. S - 34 is an isotope of sulfur, not sodium (Na has atomic number 11).
• The mass number is 34. Using the formula \( \text{Mass number}=\text{Protons}+\text{Neutrons} \), with protons = 16 (from atomic number of S), we get \( \text{Neutrons}=\text{Mass number}-\text{Protons}=34 - 16=18 \).

Answer:

contains exactly 18 neutrons.