#### Unit Conversions, Isotopes, Atomic Theory

1 kilometer

1000 meters

1 meter

100 centimeters

1 centimeter

10 millimeters

1 kilogram

1000 grams

1 gram

1000 milligrams

kilo

10^3 (one thousand)

centi

10^-2 (one hundredth)

milli

10^-3 (one thousandth)

metric conversion chart

Mass

The name of an isotope is determined by the atomic __________ of that isotope.

3

What is the atomic mass of Tritium?

1

How many neutrons are in a nucleus of deuterium?

3

How many neutrons are in an atom of Lithium-6?

5

How many neutrons are in an atom of Lithium-8?

neutrons

subatomic particles that have a neutral or no charge

protons

positively charged subatomic particles

atom

the smallest particle of an element that has all the properties of the element

electrons

negatively charged subatomic particles

nucleus

the central core of an atom; contains protons and neutrons

Picture of Dalton's Model

Picture of Thomson's Model

Picture of Rutherford's Model

Picture of the Modern electron cloud model

Description of Dalton's Model

a small sphere that is the most basic thing; cannot be broken down

Description of Thomson's Model

A sphere that is positive with small negative particles mixed within it. Like pudding

Description of Rutherford's model

A small positive core with small negative particles circling it. Like our solar system.

Cathode Ray

Experiment that showed atoms contained particles that were negatively charged.

Gold Foil

Rutherford did this experiment using alpha particles. Deflected electrons proved there was a small positively charged nucleus.

Democritus

Greek philosopher that first proposed the idea of a "atomos". That was the word for a mass that cannot be divided further. This is where the term "atom" originates.

Scientist that discovered the nucleus

Rutherford

Scientist that discovered electrons.

Thompson

atomic number

The number of protons in the nucleus of an atom

Mass number

the sum of the number of neutrons and protons in an atomic nucleus

isotope

Atoms of the same element that have different numbers of neutrons

ground state

The lowest energy state of an atom

excited state

temporary state when an electron is at a higher energy level

Picture of the Modern electron cloud model

Description of Dalton's Model

a small sphere that is the most basic thing; cannot be broken down. nicknamed the billiard (pool) ball model

Description of Thomson's Model

A sphere that is positive with small negative particles mixed within it. Like pudding

Description of Rutherford's model

A small positive core with small negative particles circling it. Like our solar system.

Niels Bohr

Showed that electrons move about the nucleus only in prescribed orbits. When jumping from one orbit to another with lower energy, a light quantum is emitted.

Scientist that discovered the nucleus

Rutherford

Scientist that discovered electrons.

Thompson