Scientist
Discovered the indivisible building block of life the atom
Democritus
represented by the atomic number
protons
Discovered the atom has a dense nucleus by emitting alpha particles in his gold foil experiment.
Rutherford
1 electron on outer energy level (valence electron)
Alkali Metals
Rows & columns of the periodic table. In that order.
Periods & families
Organized the Periodic Table by Atomic Weight; credited for the first periodic table.
Mendeleev
The only subatomic particle outside the nucleus
electron
Thought that electrons moved around the nucleus but only in prescribed orbits.
Bohr
Low chemical reactivity
Have full outer energy levels
Noble Gases
I am charged
Ion
Proposed a model of the atom which he likened to plum pudding. The negative electrons represented the raisins in the pudding and the dough contained the positive charge.
Thomson
a particle with no charge
neutron
Oil drop experiment helped to quantify the charge of an electron.
Millikan
Very reactive- not found free in nature
2 electrons on outer energy level (valence electrons)
Reacts readily with halogens and water
Silver luster in pure form, ductile, malleable
IIA
Alkaline Earth Metals
names and charges in the nucleus
protons positive neutrons negative
This atomic theory contained the following ideas:
1. All atoms of a given element are identical.
2. The atoms of different elements vary in mass and size.
3. Atoms are indestructible. Chemical reactions may result in their rearrangement, but not their creation or destruction.
Dalton
the sum of protons and average neutrons
atomic mass
Organized the Periodic Table by Atomic Number; gave rise to the modern periodic table.
Moseley
Very high reactivity- not found in elemental form in nature
Poor thermal and electrical conductors
Brittle and crumbly as solids
7 electrons in outer energy level (valence electrons)
Halogens
Masses of subatomic particles
protons =1 amu
neutrons=1 amu
electrons = 0 amu
Organized the Periodic Table by Atomic Weight; credited for the first periodic table.
Mendeleev
if you have to many neutrons you might be a
isotope
Best known for his uncertainty principle that electrons do NOT follow neat orbits and contain photons which gave rise to studies on the behavior of electrons.
Heisenberg
Contain the most common metals
Good thermal and electrical conductors
Have higher melting points, usually hard with high densities
Elements in this area exhibit many exceptions to general rules
Form brightly colored compounds
Transition Metals
Used mathematical equations to describe the likelihood of finding an electron in a certain position. This atomic model is known as the quantum mechanical model which does not define the exact path of an electron, but rather, predicts the odds of the location of the electron.
Schrodinger