Question detail
A sodium ion (Na⁺) has an atomic number of 11 and a mass number of 23. Determine the number of protons, neutrons, and electrons in the sodium ion.
Try the question, check the answer, then read the explanation to understand the curriculum point.
At a glance
Question
Type
exam_style
Style
Topic
Atomic structure
Question
A sodium ion (Na⁺) has an atomic number of 11 and a mass number of 23. Determine the number of protons, neutrons, and electrons in the sodium ion.
Answer
The sodium ion contains 11 protons, 12 neutrons, and 10 electrons.
Explanation
The atomic number of sodium is 11, which means it has 11 protons. The mass number is 23, so the number of neutrons is calculated as mass number minus atomic number: 23 - 11 = 12. Since the sodium ion has a +1 charge, it has lost one electron, resulting in 10 electrons. This question assesses the ability to determine the composition of ions based on atomic structure.
Common mistake
Misidentifying Neutrons from Mass Number
Students often subtract the atomic number from the mass number to find the number of neutrons, but then forget to adjust for the ion’s charge when calculating electrons.
Remember that the number of neutrons is always mass number minus atomic number, independent of charge. The electron count is atomic number minus the ion’s charge (negative charge means +1 electron, positive charge means –1 electron).
Related flashcards
Flashcard 1 of 5
Related practice questions
Question 1 of 5
Choose an answer, get feedback, then move sideways through the set.