Atom Review Sheet
I C.AEiS
ii fi atomics own
E
Hiii
a
orof
protons neutral
Democritus thought an atom was a hard indivisible sphere called “atomos”
John Dalton- Came up with theory called “Atomic Theory of Matter”
1. All matter is made up of tiny particles called ATOMS
2. All atoms of a given element are alike while atoms of a diff element r different
3. Compounds are formed when atoms of diff elements combine in fixed proportions
4. Atoms are indivisible- cant be created/destroyed
JJ Thompson- Developed the Cathode Ray Tube Experiment & discovered electrons
◦ discovered the “Plum Pudding Model” stating that the atom is a hard sphere w negative electrons in it
Ernest Rutherford- designed the GOLD FOIL EXPERIMENT (using alpha particles)
◦ Observed the alpha particles went straight through the gold foil = atoms are made of empty space
◦ A few of the alpha particles deflected = there is a small, dense, positively charged nucleus
Bohr Model (1911) r
◦ atom contains a small, dense, positively charged nucleus Orbits vs Orbitals
‣ surrounded by electrons in circular orbits theno
areaaround
jjjis
particularpatnan
4eatonous where an elect
Electronsdo
not isfound
◦ Bohrs model is incorrect- bec electrons don’t move in fixed orbits
Wave Mechanical Model (current atomic theory) exactlocation's
◦ energy & matter are viewed as both waves and particles (made up of tiny energy packets called “Quanta”
◦ electrons move in an electron cloud and are found in a orbital
Democritus Plum Pudding GoldFoil Model Bohr Wave
Mass Number (rounded atomic mass) (number of protons + neutrons)
◦ #neutrons = mass# - atomic#
Atomic mass- the average of the naturally occuring isotopes of a given element
Isotopes- atoms of the same element that have diff # of neutrons (isotope = neutrons)
◦ Identified by
Mg 8 or s Mg'sMg
I C.AEiS
ii fi atomics own
E
Hiii
a
orof
protons neutral
Democritus thought an atom was a hard indivisible sphere called “atomos”
John Dalton- Came up with theory called “Atomic Theory of Matter”
1. All matter is made up of tiny particles called ATOMS
2. All atoms of a given element are alike while atoms of a diff element r different
3. Compounds are formed when atoms of diff elements combine in fixed proportions
4. Atoms are indivisible- cant be created/destroyed
JJ Thompson- Developed the Cathode Ray Tube Experiment & discovered electrons
◦ discovered the “Plum Pudding Model” stating that the atom is a hard sphere w negative electrons in it
Ernest Rutherford- designed the GOLD FOIL EXPERIMENT (using alpha particles)
◦ Observed the alpha particles went straight through the gold foil = atoms are made of empty space
◦ A few of the alpha particles deflected = there is a small, dense, positively charged nucleus
Bohr Model (1911) r
◦ atom contains a small, dense, positively charged nucleus Orbits vs Orbitals
‣ surrounded by electrons in circular orbits theno
areaaround
jjjis
particularpatnan
4eatonous where an elect
Electronsdo
not isfound
◦ Bohrs model is incorrect- bec electrons don’t move in fixed orbits
Wave Mechanical Model (current atomic theory) exactlocation's
◦ energy & matter are viewed as both waves and particles (made up of tiny energy packets called “Quanta”
◦ electrons move in an electron cloud and are found in a orbital
Democritus Plum Pudding GoldFoil Model Bohr Wave
Mass Number (rounded atomic mass) (number of protons + neutrons)
◦ #neutrons = mass# - atomic#
Atomic mass- the average of the naturally occuring isotopes of a given element
Isotopes- atoms of the same element that have diff # of neutrons (isotope = neutrons)
◦ Identified by
Mg 8 or s Mg'sMg
