Greek Philosopher that called nature's basic particle an atom meaning it was indivisible
Law of Conservation of Mass
States that mass is neither created nor destroyed during ordinary chemical reactions or physical changes
Law of Definite Proportions
The fact that a chemical compound contains the same elements in exactly the same proportions by mass regardless of the size of the sample or source of the compound
Law of Multiple Proportions
If two or more different compounds are composed of the same two elements, then the ratio of the masses of the second element combined with a certain mass of the first element
Is Dalton's atomic theory that all matter is composed of extremely small particles called atoms still true today?
Is Dalton's atomic theory that Atoms of a given element are identical in size, mass and other properties still true today?
No because a given element can have atoms with different masses.
Is Dalton's Atomic theory that Atoms cannot be subdivided, created or destroyed still true today?
No Atoms are divisible into even smaller particles
Is Dalton's Atomic theory that Atoms of different elements combine in simple whole- number ratios to form chemical compounds still true today?
Is Dalton's Atomic theory that in chemical reactions, atoms are combined, separated or rearranged still true today?
What is the idea of atomism that democritus introduced?
states that matter is composed of tiny particles that cannot be further divided
the smallest particle of an element the retains the chemical properties of that element
Who discovered the Electron?
How did Thomson discover the Electron?
by measuring the ratio of the charge of cathode-ray particles to their mass. Thomson concluded that all cathode rays are composed of identical negatively called particles
What did Millikan discover?
how to measure the charge of the electron
What did Rutherford discover?
the nucleus of the atom, implying that the atom was mostly empty space
What was Rutherford's experiment?
The gold foil experiment
In rutherford's experiment what happened to the alpha particles that made them think there was a nucleus
1 in every 8000 were deflected back toward the source
The nucleus is made up of
protons and neutrons
What is The radius of an atom?
the distance from the center of the nucleus to the outer portion of its electron cloud.
What is a proton's charge?
What is an electrons charge?
Where can a neutron and proton be located?
in the nucleus
Where can an electron be located?
in the electron cloud
The number of ____ defines an element.
The sum of protons + neutrons in an element is the
the mass number
The number of protons in an element is equal to the
the atomic Number
_________ are atoms of the same element that have different masses.
How many different types of hydrogens atoms are known?
_________ is The mass number is written with a hyphen after the name of thtione element.
___________ is The superscript indicates the mass number and the subscript indicates the atomic number.
_________ is a general term for a specific isotope of an element.
________ is exactly 1/12 the mass of a carbon-12 atom.
1 amu (atomic mass unit)
_________________ of an element depends on both the mass and the relative abundance of each of the element's isotopes.
average atomic mass
A _______ is the amount of a substance that contains as many particles as there are atoms
ex. 1 mol of carbon is Carbon-12