Lecture 1- Atomic theory 1 Flashcards
1
Q
pure sample
A
- contains particles, or units, of one specific atom of molecule
- FU=ionic
- can separate with chemical or nuclear change
2
Q
Mixture
A
- contains particles, or units, of more than one specific atom or molecule
- each have their own properties
- can separate by undergoing physical change
3
Q
Democritus
A
- all matter made up of very small, individual particles called atoms
4
Q
Antoine Lavoisier
A
- father of chemistry
- law of conservation of matter
- gave oxygen its name and showed it was involved in combustion reactions
5
Q
Aristotle
A
4 elements
- sided with him over Democritus
6
Q
Joseph Proust
A
- law of definite proportions
7
Q
Law of definite proportions
A
- joseph proust
- different pure samples of the same compound always contain the same proportions of each element by mass
- ex. water is always 88.8% oxygen and 11.2% hydrogen by mass
8
Q
John Dalton
A
- law of multiple proportions
- atomic molecular theory
- if elements were made of tiny indivisible particles, then molecules of a particular compound would always be composed of equal numbers of each type of element
- thus, each element in a given compound would account for a consistent percentage of that compounds mass
9
Q
Daltons 4 postulates
A
- Each element is composed of tiny particles called atoms
- All atoms of a given element are identical and all atoms of different elements are different (wrong because isotopes)
- Atoms are not crested or destroyed in chemical reactions. They are dissociated, combined, or recombined
- Compounds are formed when atoms of different elements combine with one another. A given compound always contains the same relative numbers and types of atoms
10
Q
JJ Thompson
A
- used cathode ray tube to discover electrons
- stream of particles made a green glow and were attracted towards the positive side
- calculated charge to mass ratio
- plum pudding
11
Q
Earnest Rutherford
A
- Gold foil experiment
- Beta particles toward positive= negative- much deflection
- Alpha towards negative= positive- more mass, didn’t reflect as much
- gamma= neutral- highspeed photon
12
Q
Gold foil experiment
A
- Nucleus is a very small positively charged core containing protons and neutrons
- negatively charged electrons are extremely tine and occupy the vast majority of the atoms volume
13
Q
sub atomic particles
A
Proton- +1, 1amu
Electron- -1, .0005amu
Neutron- 0, 1amu
14
Q
Mass number
A
Equal to the number of protons plus the number of neutrons
15
Q
atomic number
A
number of protons