Chapter 4 Chemistry

Front 1

Democritus

Back 1

First person to propose that matter wasn't infinitely invisible. Atoms cannot be created, destroyed, or further divided

Front 2

Aristotle

Back 2

Atoms moved through empty space. Matter is made of earth, fire, air, and water

Front 3

John Dalton

Back 3

Matter is composed of atoms; atoms are identical in size, mass, and chemical properties for a given element. Dalton's atomic theory

Front 4

Sir William Crookes

Back 4

Accidentally discovered cathode ray that led to the invention of television

Front 5

J. J. Thomson

Back 5

Began cathode ray experiments to determine the ratio of its charge to its mass. He determined that ratio. Identified first subatomic particle- electron. Plum Pudding Model

Front 6

Rutherford

Back 6

Discovered nucleus and protons

Front 7

Chadwick

Back 7

Discovered neutrons

Front 8

Henry Mosley

Back 8

Atomic number = number if protons; atoms of each element contain unique positive charge in their nuclei

Front 9

Atom

Back 9

The smallest particles of an element that retains all the properties of that element

Front 10

Cathode Ray

Back 10

Radiation that originates from the cathode and travels to the anode of a cathode ray tube

Front 11

Atomic Number

Back 11

The number of protons in an atom

Front 12

Isotope

Back 12

Atoms of the same element with different numbers of neutrons

Front 13

Mass Number

Back 13

The number after an elements name representing the sum of its protons and neutrons

Front 14

Atomic Mass Unit

Back 14

One twelfth the mass of a carbon-12 atom

Front 15

Atomic Mass

Back 15

The weighted average mass of the isotopes of that element

Front 16

Radioactivity

Back 16

The process in which some substances spontaneously emit radiation

Front 17

Radiation

Back 17

The rays and particles that are emitted by radioactive materials

Front 18

Nuclear Reaction

Back 18

A reaction that involves a change in the nucleus of an atom

Front 19

Radioactive Decay

Back 19

A spontaneous process in which unstable nuclei lose energy by emitting radiation

Front 20

Alpha Radiation

Back 20

Radiation that is made up of alpha particles; is deflected towards a negatively charged plate when radiation from a radioactive source is directed between two electrically charged plate

Front 21

Alpha Particle

Back 21

A particle with two proton and two neutrons with a 2+ charge

Front 22

Nuclear Equation

Back 22

A type of equation that shows the atomic number and mass number of the particles involved

Front 23

Beta Radiation

Back 23

Radiation made up of beta particles; is deflected towards positively charged plate when radiation from a radioactive source is directed between to electrically charged plates

Front 24

Beta Particle

Back 24

A high speed electron with a 1- charge during radioactive decay

Front 25

Gamma Ray

Back 25

High energy radiation that has no charge or mass and is not deflected by electric or magnetic fields. It accounts for most of the energy lost during radioactive decay

Front 26

Electron

Back 26

Discovered in 1932; Cathode Rays; Identified by Thomson;

Front 27

Nucleus

Back 27

Caused large deflections of alpha particles in Rutherford's experiment