Butler Chemistry Unit 2

Front 1

Dalton's Atomic Theory

Back 1

A theory proposed by John Dalton in 1808, based on numerous scientific experiments that marked the beginning of the development of the modern atomic theory

Front 2

Atom

Back 2

The smallest particle of an element that retains all the properties of that element; It is electrically neutral, spherically shaped, and composed of electrons, protons, and neutrons

Front 3

Cathode Ray

Back 3

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

Front 4

Electrons

Back 4

Negatively charged particles that are part of all forms of matter

Front 5

Nucleus

Back 5

The extremely small, positively charged, dense center of an atom that contains positively charged protons, neutral neutrons, and is surrounded by empty space through which one or more negatively charged electrons move

Front 6

Proton

Back 6

A subatomic particle carrying a charge equal to but opposite that of an electron

Front 7

Neutron

Back 7

A neutral subatomic particle in an atom's nucleus that has a mass nearly equal to that of a proton

Front 8

Atomic Number

Back 8

The number of protons in an atom

Front 9

Isotope

Back 9

Atoms with the same number of protons, but different number of neutrons

Front 10

Mass Number

Back 10

The number added after an element's name that represents the sum of the number of protons and neutrons in the nucleus

Front 11

Atomic Mass Unit (amu)

Back 11

1/12th the mass of a Carbon-12 atom

Front 12

Atomic Mass

Back 12

The weighted average mass of the isotopes of an element

Front 13

Nuclear Reactions

Back 13

Reactions involving an atom of one element changing into an atom of another element; Change in nucleus

Front 14

Radioactivity

Back 14

A process in which some substances spontaneously emit radiation

Front 15

Radiation

Back 15

The rays and particles emitted by a radioactive material

Front 16

Radioactive Decay

Back 16

A process in which unstable nuclei lose energy by emitting radiation

Front 17

Alpha Radiation

Back 17

Radiation deflected toward negatively charged plates

Front 18

Alpha Particles

Back 18

These make up alpha radiation; Each of these contains 2 protons and 2 neutrons, thus having a 2+ charge

Front 19

Nuclear Equation

Back 19

Shows the atomic number and mass number of the particles involved

Front 20

Beta Radiation

Back 20

Radiation deflected toward positively charged plates

Front 21

Beta Particles

Back 21

Fast moving electrons that make up beta radiation

Front 22

Gamma Rays

Back 22

High-energy radiation that possess no mass and are denote by the symbol 8y

Front 23

Mole (mol)

Back 23

The SI base unit used to measure the amount of a substance (1 of these = 6.02 X 10^23)

Front 24

Avogadro's Number

Back 24

The number 6.022 136 7 X 10^23, which is the number of representative particles in a mole, and can be rounded to three significant digits: 6.02 X 10^23

Front 25

Molar Mass

Back 25

The mass in grams (g) of one mole of any pure substance

Front 26

Percent Composition

Back 26

The percent by mass of each element in a compound

Front 27

Empirical Formula

Back 27

A formula with the smallest whole-number ration of the elements

Front 28

Molecular Formula

Back 28

A formula that specifies the actual number of atoms of each element in one molecule or formula unit of the substance

Front 29

Hydrate

Back 29

A compound that has a specific number of water molecules bound to its atoms