Chapter Four (Sections 1-2)

Question 1

Atom

Answer 1

The smallest unit of an element that maintains the properties of that element.

Question 2

Electron

Answer 2

A subatomic particle that has a negative charge.

Question 3

Nucleus

Answer 3

In physical science, an atom’s central region, which is made up of protons and neutrons.

Question 4

Electron Cloud

Answer 4

A region around the nucleus of an atom where electrons are likely to be found.

Question 5

Proton

Answer 5

A subatomic particle that has a positive charge and that is found in the nucleus of an atom.

Question 6

Atomic Mass Unit

Answer 6

A unit of mass that describes the mass of an atom or molecule.

Question 7

Neutron

Answer 7

A subatomic particle that has no carge and that is found in the nucleus of an atom.

Question 8

Atomic Number

Answer 8

The number of protons in the nucleus of an atom; the atomic number is the same for all atoms of an element.

Question 9

Isotope

Answer 9

An atom that has the same number of protons as other atoms of the same element do but that has a different number of neutrons.

Question 10

Mass Number

Answer 10

The sum of the numbers of protons and neutrons in the nucleus of an atom.

Question 11

Atomic Mass

Answer 11

The mass of an atom expressed in atomic mass units.

Question 12

Democritus

Answer 12

Thought that you would eventually end up with a particle that can’t be cut.

Question 13

Dalton

Answer 13

Believed that everything is made of atoms, atoms of the same element are exactly alike while atoms of different atoms are different, and that atoms join with other atoms to make new substances.

Question 14

Thomson

Answer 14

Discovered that there are smaller particles inside the atom. Did the plum pudding model.

Question 15

Bohr

Answer 15

Studied the way atoms react to light. He proposed that atoms move around in certain paths.

Question 16

Rutherford

Answer 16

Designed an experiment to study the parts of the atom. He did the gold foil experiment.