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

both adhesion and cohesion are attractions.

they are different in that adhesion is the force of attraction between the molecules of two different substances, whereas cohesion is the force of attraction between molecules of the same substance.

possible examples include capillary action, in which the adhesion between water and glass causes the water to rise in a narrow tube against the force of gravity.

because of hydrogen bonding, water is extremely cohesive.

this causes molecules on the surface of water to be drawn inward, which is why drops of water form beads on smooth surfaces.

hope this .

they it depends on if one believes about radioactivity, they make a geiger counter beep but maybe it was going to beep anyway electronics do wierd things all the time or it was programmed to beep near certain metals.