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

Question

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.