Studied by 0 people
Looks like no one added any tags here yet for you.
Greek Philosophers
Democritus and Leucippus
Democritus’ proposal:
the world is made of space and particles, which are not indivisible
Aristotle’s proposal:
all matter made of a blend of fire, air, earth, and water; when u combine these all u get HYLE
Instead of experiments, they used:
debates and arguing
Between Democritus and Aristotle who won society’s support? Why?
Aristotle won due to popularity and his theory was the precedent for the Middle Ages.
John Dalton’s Laws
Law of Conservation of Mass
Law of Multiple Proportions
Dalton’s Atomic Theory
Combined Aristotle’s elements and atoms and had scientific evidence to support him
Law of Definite Proportions, who made it?
Proust
Law of Definite Proportions states:
Specific substances always contain elements in the same ratio by mass
Law of Conservation of Mass, who?
Antoine Lavoisier
Law of Conservation of Mass states:
In ordinary reactions, matter can be changed but it can’t be created/destroyed
“The Father of Modern Chemistry”
Antoine Lavoisier
he …
found 33 elements
devised the metric system
discovered combustion as the reaction with oxygen
Antoine Lavoisier
Dalton also proposed another law but had now evidence for it, what law was this?
Law of Multiple Proportions
Law of Multiple Proportion was supported by:
Gay - Lussac
Avogado’s Hypothe
The Law of Multiple Proportions states:
The ratio of masses of one element combined with another element can be expressed in small whole numbers
Atom
Smallest piece of an element that retains the properties of that element
Dalton stated atoms are indivisible, was he correct?
No, atoms are made up of smaller subatomic particles
types of rays emitted by radioactive substances:
Alpha particles
Beta Particles
Gamma Rays
What are the charges of the 3 rays mentioned
Alpha: positive, deflects off + plate
Beta: negative, deflects off - plate
Gamma: no charge
Along with no charge, what else do Gamma Rays not have?
no mass and no deflection
Who discovered the electron?
jj Thomson
What did Thomsons atomic model describe?
An atom is a sphere of positive electricity in which negative electrons are embedded
Who determined the charge to mass ratio of an electron?
JJ Thomson
Alpha Particles=
Helium atoms - electrons
Rutherford found in his gold foil experiment that:
An atom is mostly empty space
There is a small, dense, and positive piece in the center called the Nucleus
Alpha particles are deflected by it if they get close enough
