Quiz Chapter 4

Question 1

What is the defintion of an atom?

Answer 1

An atom is the smallest particle of an element that retains its identity in a chemical reaction. pg. 102

Question 2

Explain how Ernest Rutherford’s gold foil experiment showed that the atom had a dense, positively charged nucleus

Answer 2

In Rutherford’s gold foil experiment, alpha particles went straight through the gold foil, but a small fraction of the alpha particles bounced off the gold foil at very large angles, and some even bounced back toward the source. This proved that the nucleus is densely packed and positively charged. The reason his experiment proves this, is that the reason the particles bounced back towards the source because the particles were hitting the nuclei of other particles. pg. 108

Question 3

Match the subatomic particle to it’s electrical charge value.
neutron
proton
electron

Answer 3

0
+1
-1

Question 4

A proton and an electron are similar in size.

Answer 4

False.

Question 5

Explain why an atom that loses 2 electrons must then have a charge of +2.

Answer 5

When it loses 2 electrons, the atom will have two more protons than electrons. Since protons carry a 1+ charge and electrons carry a 1- charge, this will leave it with an overall charge of 2+.

Question 6

Atomic Number

Answer 6

number of protons in an atom

Question 7

Atomic Mass

Answer 7

The average of the masses of the isotopes of an element weighted by their relative natural abduncances

Question 8

Mass number

Answer 8

the number of protons + the number of neutrons in an atom

Question 9

Isotope

Answer 9

atoms with the same number of protons but different number of neutrons

Question 10

Atomic Mass Unit

Answer 10

1/12 the mass of a carbon-12 atom