History Of Atomic Structures Flashcards
Boyle
The first to re-define “element”
Element
Substance that can not be broken down into simpler substances
Lavoisier
Used oxygen and phlogiston
Proust
Law of definite proportions
Compounds have defined chemical formulas
Dalton’s atomic theory
I. All matter is composed of indivisible particles called atoms
II. All atoms of a given element are identical; atoms of different elements have different properties
III. Chemical reactions involve the combination of atoms, not the destruction of atoms
IV. When elements react to form compounds, they react in defined, whole number rations
Why is it Dalton’s theory and not Dalton’s law
Because of isotopes
Atomic number
The number of protons in an atom.
It determines the identity of the atom
Atomic mass
The sum of the protons and neutrons
Subatomic particles:
Protons
Neutrons
Electrons
Protons
Found in nucleus - positively charged
Neutrons
Found in nucleus -neutral - no charge
Electrons
In outer shell/electron cloud -negative charge
Isotope
Atom with the same number of protons but different number of neutrons
Democritus
Developed a new theory on matter, first to use the
“atomas”- indivisible
Periodic table
Shows all of the known elements w/ information about them
They are organized by atomic number with horizontal rows and vertical columns