Exam 1 Flashcards
people and what they did + laws
Democritus
coined the term atomos – meaning indivisible or uncuttable
Who coined the term atomos?
Democritus
John Dalton
The theory that atoms are the fundamental building blocks of matter
HIS theory was based on four postulates
Alchemists
what was john daltons first postulate?
Each element is composed of extremely small particles call atoms
true
what was john daltons second postulate?
All atoms of a given element are identical to one another but the atoms of one element are different from the atoms of all other elements
false
what is john daltons third postulate?
atoms of an element are not changed into atoms of a different element by chemical reactions: atoms are neither create nor destroyed in chemical reactions.
Instead they just reaarange
true
What was john daltons fourth postulate?
Compounds are formed when atoms of more than one element combine: a given compound always has the same relative number and kind of atoms.
same relative number and kind of atoms
compounds = atoms of more than one element combine
What is the law of constant composition?
In a given compound the relative numbers and kinds of atoms are constant
What is the law of conservation of mass?
The total mass of substances present at the end of a chemical process is the same as the mass of substances present before the process took place
MATTER IS NEITHER CREATED NOR DESTROYED
what is the law of multiple proportions?
If two elements A and B combine to form more than one compound the mass of B that can combine with a given mass of A are in the ration of small whole numbers
Who was Henri Becquerel?
He the first person to observed Radioactivity
Who was Marie and Pierre Curie?
They studied also studied radioactivity
What are the 3 types of radiation?
Alpha particles
Beta particles
Gamma rays
What are ALPHA particles?
Helium Nucleus
What are Beta particles?
High Speed Electrons e-
What is gamma rays?
energy
Who was JJ Thomson?
He was responsible for the “plum pudding” model of the atom
Who was Ernest Rutherford?
shot alpha particles at a thin sheet of gold foil and observed the pattern of the scattered particles
DISCOVERY OF THE NUCLEUS
What is a diatomic molecule?
Two atom molecules
what are the elements always found as diatomic molecules under “normal conditions”
N (nitrogen)
O (oxygen)
F (fluorine)
Cl (chlorine)
Br (bromine)
I (iodine)
H (hydrogen)
What is a homogeneous mixture?
Uniform ex. smoothie
What is a heterogeneous mixture?
No uniform
ex. salad
What is melting?
Becoming liqiudfied by heat
What is freezing?
Below 32 F
