How many electrons surround the nucleus of a neutral atom of the isotope ¹⁸O of oxygen?
A) 18
B) 7
C) 10
D) 8

Question

Quizplus · Accepted Answer

The atomic number of oxygen is 8, which means it has 8 protons in the nucleus. Since the oxygen atom is neutral, it must also have 8 electrons surrounding the nucleus. The isotope ¹⁸O indicates that the oxygen atom has an atomic mass of 18, which means it has 10 neutrons in the nucleus. The number of electrons in an atom is determined by its atomic number (which is 8 for oxygen), not its mass number (which is 18 for this particular isotope). Therefore, a neutral atom of the isotope ¹⁸O of oxygen has 8 electrons surrounding its nucleus.

How Many Electrons Surround the Nucleus of a Neutral Atom