Question

Zinc has the chemical symbol Zn and the atomic number 30. How many protons, neutrons, and electrons does an atom of zinc-69 have?

30 protons, 39 neutrons, 39 electrons
39 protons, 30 neutrons, 30 electrons
39 protons, 30 neutrons, 39 electrons
30 protons, 39 neutrons, 30 electrons

Answer 1

An atom's atomic number indicates the number of protons and electrons it contains. For zinc (Zn), which has an atomic number of 30, it has:

- **30 protons**
- Since zinc-69 is a specific isotope of zinc, we can find the number of neutrons by subtracting the atomic number from the mass number (which is 69 for zinc-69):
- Neutrons = Mass number - Atomic number = 69 - 30 = 39 neutrons

- The number of electrons in a neutral atom equals the number of protons, thus zinc-69 also has **30 electrons**.

Putting this together, the correct counts are:
- **30 protons**
- **39 neutrons**
- **30 electrons**

So, the correct choice from the options you provided is:

**30 protons, 39 neutrons, 30 electrons**.