People
Thought that all matter was composed of small, indivisible particles
Who is Democritus?
The minimum amount of energy that can be gained or lost by an atom
States that any orbital can only hold two electrons, both with different spins. It is impossible for any two electrons to have the exact same set of 4 quantum numbers
What is the Pauli Exclusion Principle?
Refers to the average kinetic energy
-measured in Celsius, Fahrenheit, and Kelvin
What is temperature?
Sphere-shaped orbital
What is an s orbital?
He wanted to prove that atoms are mostly empty space, so he fired alpha (+) particles at gold leaf foil: -most went straight through or were slightly deflected,
-while some bounced straight back.
Conclusions:
1. Most of the atom is empty space,
2. The atom has a dense, tiny positively charged core (nucleus),
3. The electrons (-) whirl around the outside of the nucleus.
He measured the diameter of the nucleus to be 1 / 100,000 the diameter of the atom.
Who is Ernest Rutherford?
Occurs when an atom returns to its stable state
What is the emission of light to release energy to become stable?
States that atoms are most stable with a full outer shell.
What is the Octet Rule?
The type of change in which the identity of substances does not change
What is a physical change?
What is a p orbital?
1. Elements are composed of atoms that cannot be further broken down
2. Atoms are neither destroyed nor created in chemical reactions
3. All atoms of given element weigh the same; different elements weigh different amounts 4. Elements can be ordered according to weight
Who is John Dalton?
The distance between peaks of the waves or between any two identical points on neighboring waves.
What is wavelength?
Tells us that electrons enter orbitals of equal energy one at a time with parallel spins, before coming back and pairing up.
What is Hunds Rule?
Different substance formed. Describes how a certain type of matter will react and change (or not react and change) when it is in the presence of other kinds of matter.
What is a chemical change?
λ
What is wavelength?
Devised a system with fluorescent material that glowed when struck by charged particles which provided a way to measure the deflection of a beam in a CRT (or Crooke's tube)
Who is JJ Thomson?
The number of waves that go by each second. A complete wave is called a cycle.
What is frequency?
States that you must completely fill up any set of orbitals (with lowest energy first) before moving on and placing electrons in the next higher energy level.
What is the Aufbau principle?
Substances composed of a single type of atom.
What is an element?
V
What is frequency?
Proposed that electrons are arranged in concentric circular paths or orbits around the nucleus. Electrons in a particular path have a fixed energy, thus they do not lose energy and fall into the nucleus. Experiments were based on the hydrogen atom. Results did not hold true for other elements.
Who is Neils Bohr?
Higher energy levels of an electron
What are excited states?
The electrons in the highest occupied energy level
What are valence electrons?
Mixture composed of more than identifiable component; differences can be seen with the naked eye.
What is a heterogeneous compound?
c
What is the speed of light?