Unit 2 Atomic Theory

Element

Substance cannot be broken down further by chemical means

Compound

Two or more elements with distinct properties and definite composition

Homo Mix

Not chemically united with uniform composition

Hetero Mix

Not chemically united with non uniform composition

Democritus

Atom as indivisible unit of matter

John Dalton

Atomic theory

Antoine Lavoisier

Discover O, created naming system for compound, law of conservation of mass

JJ Thompson

Cathod ray to discover electrons and mass to charge ratio + plum pudding model

Robert Millikan

Oil drop experiment to find the charge of electron

Ernest Rutherford

Gold foil experiment to discover central nucleus and created planetary model and classified radioactivity into alpha beta gamma

Group 1

Alkali metals

Group 2

Alkaline earth metals

Group 3-12

Transition metals

Group 15

Pnictogens

Group 16

Chalcogens

Group 17

Halogens

Group 18

Noble gases

Empedocles

World made of water fire air earth

Paracelsus

World made up of mercury sulfur salt

Boyle

World made of elements

John Newlands

Ordered elements by atomic weight

Dmitri Mendeleev

First periodic table

Cation

Positively charged ion

Anion

Negatively charged ion

Nuclear force

Overcomes electrostatic repulsion between protons to hold the nucleus together

Nuclear force is … and …

Strong and short

Proton

Up up down quarks

Neutron

Up down down quarks

Nuclei that contain … protons or neutrons are generally more stable (MAGIC NUMBERS)

2, 8, 20, 50, 82, 126

Most stable

Even even

Least stable

Odd odd

Nuclear binding energy

Energy required to break up nucleus into protons and neutrons

Mass defect

Missing mass converted to energy

Up left to right on BOS

Fusion

Up right to left on BOS

Fission

Radioactive decay example of

Nuclear transmutation when atom of one element turn into atoms of another

Alpha

4/2 occurs when nucleus is too heavy

Beta minus

0/-1 occurs when too many neutrons

Beta plus (positron)

0/+1 occurs when too many protons

Electron capture

Captures core electron + proton to form a neutron

Gamma

0/0 occurs after other decay when atom needs to emit extra energy

Short half life

Fast decay

Long half life

Slow decay

Artificial nuclear transmutation

Bombard nuclei with other particles

Chadwick

Discovers neutron

Nuclear fission

Heavy nucleus splits apart to form two or more lighter nuclei

Moderator in fission reaction

Slow down neutrons

Control rod in fission reaction

Absorb neutrons

Nuclear fusion

Two nuclei come together and merge to form a heavier nucleus & typically only take place at higher temperatures

Hydrogen bomb

Fission causes fusion

Sun

Fusion of H into He to generate energy

Cyclotron

Particle accelerators

Rapidly expanding gases

Water vapor, carbon dioxide, carbon monoxide

Ammonium nitrate fuel oil

Hard to set off & explosion breaks bonds of ANFO causing it to rearrange to more stable gasses

Nitrogen tri iodine

Easy to set off

C4 (RDX)

Twice explosive power of ANFO

Steel wool acts as

Catalyst & facilitates reaction without being affected by it