6. What is the number of moles of KF in a 29 gram sample? a. 59.0 mols
C. 2.0 mols
b. 470 mols
d. 1684.9 mols

Explanation:

According to the atomic model of Rutherford, an atom has most of empty space inside the region where electrons reside.

And, nucleus is the smaller part that is, present at the center of an atom. It is solid and inside the nucleus there are  protons and neutrons are present.

When radiation hits a solid particle then they hit the positively charged nucleus due to the positive charge of protons. So, they tend to face a strong repulsion and then they retrace the path. As a result, they make it through the substance.Now, at the atomic level they hit the nucleus of the atom that s, positively charged.Particles that are not shielded or blocked by material tend to pass directly through the large empty space as in this empty space there is no repulsion because of nucleus. As a result, they tend to pass directly through the material without any disturbance. Denser is a substance, larger will be its nucleus. This means that then there will be more number of protons and neutrons inside the nucleus.  Hence, there will be high positive charge on the nucleus and very less free space that will allow very less number of radiations to pass through without any disturbance.

Thus, denser substance will shield better as compared to the lighter substances.