Atomic Theory Flashcards
(48 cards)
Conservation of Mass
matter is neither created nor destroyed
Who wrote the conservation of mass
Lavoisier in 1787
All samples of the same compound contain the same proportions by mass of the component elements
Law of Definite Composition, Proust 1804
When combining two elements to make different compounds, the masses combine in whole number ratios
Law of Multiple Proportions, Dalton 1808
Who created atomic theory
John Dalton
Postulate 1
all matter is composed of exceedingly small, indivisible particles called atoms
Postulate 2
All atoms of a given element are identical both in mass and in chemical properties. However, atoms of different elements have different masses and different chemical properties
Postulate 3
Atoms are not created or destroyed in chemical reactions. They are simply rearranged.
Postulate 4
Atoms combine in simple, fixed, whole-number ratios to form compounds.
Who discovered electrons?
JJ Thompson (1897)
What device was used to discover the electron?
Cathode Ray
Who discovered the nucleus?
Ernest Rutherford (1911)
Who created the plumb putting model?
JJ Thompson
Who were the earliest people to have ideas about atoms?
Democritus and Leucippus
Democritus came up with the name atomos, which means?
uncuttable
Who created the first scientific model of an atom?
John Dalton
What experiment confirmed the existence of a nucleus?
Gold foil experiment by Rutherford
When was the nuclear model first created
1911
Who created the planetary model of an atom?
Neils Bohr (1913)
atoms of an element with the same number of protons, but a different number of electrons
Isotopes
Elements exist in nature as a ________ of isotopes
mixture
A charged atom that has gained or lost electron(s)
Ion
ion with a positive charge
cation
ion with a negative charge
anion
