Zinc has the chemical symbol zn and the atomic number 30. how many protons, neutrons, and electrons does an atom of zinc-69 have? a. 30 protons, 39, neutrons, 39 neutrons b. 39 protons, 30 neutrons, 30 neutrons c. 39 protons, 30 neutrons, 39 electrons d. 30 protons, 39, neutrons, 30 electrons

D. 30 protons, 39 neutrons, 30 electrons

Explanation:

The atomic number (Z) is the number of protons (p) in the nucleus. Since

Z = 30, p = 30.

In a neutral atom, the number of electrons (e) equals the number of protons. Since p = 30, e = 30.

The mass number (A) is the number of protons plus the number of neutrons (n).

A = p + n

For an atom of zinc-69,

69 = 30 + n     Subtract 30 from each side and transpose

n = 39

the answer is c i believe

a 20-cm-long, cylindrical graphite (pure carbon) rod is inserted into an oxidizing atmosphere at 1145 k and 1.013 x 105 pa pressure. the oxidizing process is limited by the diffu- sion of oxygen counterflow to the carbon monoxide that is formed on the cylindrical surface.