Found that the atom was mostly empty space. Discovered the nucleus of the atom using the Gold Foil experiment.
Rutherford
200
The horizontal rows (left to right) are called what?
Periods
200
Helium has how many neutrons in its nucleus?
2
4-2 = 2
200
Lithium is in which period?
2
300
Which Atom has 2 electrons?
Helium
electrons = protons
300
Said that atoms of an element are exactly alike (number of protons, neutrons, electrons) and atoms of different elements are different.
Dalton
300
The vertical columns on the periodic table are called..
Groups
300
Draw for Nitrogen
Teacher
300
How many valence electrons does magnesium have?
HINT: draw a Bohr Model
2
400
Electrons exit in what?
The Electron Cloud
400
Made the current modern day "electron cloud" theory of the atom.
Schrodinger and Heisenberg
400
How many groups are on the periodic table?
18
400
Draw for Lithium
Teacher
400
What is a valence electron?
Outermost electron
500
The first person to discuss the idea of the atom.
Democritus
500
Said electrons orbit in fixed, circular paths around the nucleus.
Bohr
500
How many periods are on the periodic table?
7
500
Draw for Flourine
Teacer
500
Compare and contrast Bohr Models and the modern day Cloud Model.
Alike: protons/neutrons in the nucleus and electrons outside of the nucleus
Different: Bohr model's electrons orbit in fixed paths while the cloud model has them zipping around within the cloud.