Chem H Unit 1

Democritus

Discovered the atom

Atomos

Greek for invisible

Matter is made of atoms

John Dalton’s atomic theory (true)

Atoms combine in specific ratios forming compounds

John Dalton’s atomic theory (true)

In reaction atoms are rearranged

John Dalton’s atomic theory (true)

Atoms of an element are identical

John Dalton’s atomic theory (false)

Atoms cannot be divided

John Dalton’s atomic theory (false)

Plum pudding model by JJ Thompson

J. J. Thompson

Discovered electrons (were embedded in a positive mass)

Nuclear model by Earnest Rutherford

Earnest Rutherford

Discovered nucleus and protons

Earnest Rutherford

Determined atoms are predominantly empty space

Earnest Rutherford

Electrons are far from the nucleus

Earnest Rutherford

Nucleus is small, dense, and positive

Planetary Model by Niels Bohr

Niels Bohr

Determined electrons orbit in specific energy levels

Moseley

Arranged elements by atomic number

Mendeleev

Russian scientist; first noticed that elements arranged by increasing mass showed similar properties

Law of definite proportions

Ratio of elements in a compound does not change with the mass of the compound

Law of multiple proportions

Different ratios of the same elements can form different compounds

Conservation of mass

Matter is neither created nor destroyed by chemical reactions or physical changes

Protons

Positive

Changes the element

Neutrons

Neutral

Changes the mass

Electrons

Negative

Changes charge and form bonds

Fission

Breaks apart

Fission

Utilized in power plants

Fission

Reacts don’t always make the same products

Fission

Fusion

Combination of nuclei

Fusion

Deuterium

Fusion

Fusion and Fission

Tzar Bomb

Fusion and Fission

Energy = Mass x Speed of light squared (E=MC2)

Fusion and Fission

Total number of protons and neutrons stay the same during nuclear reactions

Fusion and Fission

The arrangement of protons and neutrons changed (and this the element) in both fission and fusion

Heavy water

1 in 1000 water molecules with a heavy isotope of hydrogen bonded

Transmutation

The changing of one element into another

Nuclide

The protons and neutrons in a nucleus

H-2

Deuterium

H-3

Tritium

Periodic Law

The physical and chemical properties of the elements are periodic function of their atomic number

Valence electrons

The electrons occupying the outermost energy levels of an atom. Most elements want to have 8.

Atomic radius

The average distance from the center of an atoms nucleus to its outermost electrons