Chem chapter 3 vocab

Democritus

Democritus

Greek philosopher that said all matter is made of tiny particles called "atomos" or atoms. He thought that atoms were "indivisible." his work was not based off any expiriments

Aristotle

Greek philosopher who said all matter was continuous. this idea was accepted for nearly 2000 years.

Antoine Lavoisier

founder of law of conservation of mass

JJ Thomson

founder of law of definite proportions

J J Thomson

discovered the isotope

JJ Thomson

discovered the electron with ray cathode experiment

john dalton

founder of law of multiple proportions

Amedeo Avogadro

explained the relationship between mass and number of atoms using 6.02x10^23

isotope

Atoms of the same element that have different masses (numbers of neutrons)

Henry Moseley

found the average atomic number of an element

mass number

the total number of protons and neutrons in a nucleus.

atomic number

number of protons

neucleon

protons and neutrons (particles in the neucleus)

nuclide

a general term for a specific isotope of an element (ex: chlorine-37)

Ernest Rutherford

Discovered the nucleus, gold foil experiment

Ernest Rutherford

discovered the proton

electron

A subatomic particle that has a negative charge and found outside the nucleus

proton

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

nuclear forces

short-range proton-neutron, proton-proton, and neutron-neutron forces hold the nuclear particles together

law of conservation of mass

Matter is neither created nor destroyed

Dalton's Atomic Theory

1. elements are composed of atoms.

2. atoms of same element are identical, but differ from other elements.

3. atoms can not be created, destroyed, or subdivided

4. elements can mix together to from chemical compounds

5. in chemical reactions, atoms are combined, separated, or rearranged

Dalton's incorrect theories

-Atoms are divisible into even smaller particles.

-A given element can have atoms with different masses (isotopes)

atom

Smallest particle of an element

Robert Millikan

used the oil-drop apparatus to determine the charge of an electron

JJ Thomson and Millikan

calculated he mass of an electron to be aprox. 2000 times smaller than a hydrogen atom

JJ Thomson and Millikan

determined charge to mass ratio of an electron

Sub-atomic particles

protons, neutrons, electrons

1.0073

actual mass (amu) of a proton

1.00879

actual mass of an neutron

0.000549

actual mass of an electron