Question

1. all oxygen atoms have 8 protons. circle the letter of the number of neutrons in an atom of oxygen - 18.

a. 8
b. 9
c. 10
d. 18

Explanation:

Step1: Recall the formula for mass number

The mass number \(A\) of an atom is given by \(A = p + n\), where \(p\) is the number of protons and \(n\) is the number of neutrons.

Step2: Identify the values for oxygen - 18

For oxygen - 18, the mass number \(A = 18\) and the number of protons \(p=8\) (since all oxygen atoms have 8 protons).

Step3: Solve for the number of neutrons

Using the formula \(n=A - p\), substitute \(A = 18\) and \(p = 8\). So \(n=18 - 8=10\).

Answer:

C. 10