Fundamental Chemistry Concepts Flashcards
Chemistry
_____ believed that matter is composed of very small, indivisible particles known as atomos.
Democritus
_____’s Atomic Theory states that:
(1) All matter is composed of indivisible atoms.
(2) An element is a type of matter composed of only one kind of atom, each atom of a given kind having the same properties.
(3) Compounds are composed of atoms of more than one element.
(4) A chemical reaction does not result in their creation or destruction.
John Dalton
The Law of Conservation of Mass states that
The Law of Definite Proportions by Joseph Proust states that _____.
Different samples of the same compound always contain its constituent elements in the same proportion by mass.
The Law of Multiple Proportions states that _____.
Different compounds made up of the same elements differ in the number of atoms of each kind that combine.
The _____ experiment lead to the discovery of electrons.
Cathode Ray
_____ held that atoms are uniform spheres of positively charged matter in which electrons are embedded.
JJ Thomson
_____ discovered the nucleus, which is a dense central core within the atom.
Ernest Rutherford
According to Ernest Rutherford, the nucleus is composed of positively charged particles called _____.
Protons
__% of the mass of an atom is in the nucleus.
99.5
_____ discovered the presence of neutrons in the nucleus of an atom.
James Chadwick
Mass of Subatomic Particles
Electron = _____
Proton = _____
Neutron = _____
Electron = 9.10938 x 10^-28 grams
Proton = 1.67262 x 10^-24 grams
Neutron = 1.67493 x 10^-24 grams
Note:
mass P = mass N = 1840 x mass E
The Electron Bohr Model, which was discovered by _____, shows that _____.
Neils Bohr; Electrons in an atom are confined to specific orbits.
_____ is the distance between identical points on successive waves.
Wavelength (λ)
