History of Atoms
Greek Philosopher who who called the smallest particle atomos.
Democritus
Each type of atom is represented by a solid sphere with a difference mass.
Dalton's Model
a region of space around the nucleus where electrons are most likely to be found
orbitals
These have no electrical charge
neutrons
Elements in Group 1A
alkali metals
He believed all substance were made of 4 elements.
Aristotle
Model that identified negative particles
Thomson's Model
Samples of pure compound always have the same elements in the same mass proportion
Law of constant composition
The number of protons in an atom
Atomic Number
Elements in Group 2A
alkaline earth metals
Four elements from Aristotle's view of matter
air, fire, earth, water
The model showing how an atom could be neutral and contain negative particles
Plum Pudding Model or Blueberry Muffin
Matter cannot be created or destroyed but can change form
Law of Conservation of mass
Three properties that distinguish and electron from a proton
Mass, charge, and location
Elements in Group 3A
Boron Group
Four qualities Of Aristotle's view of matter
hot, dry, cold, and wet
a dense mass with a concentrated positively charge located in the center of the atom
Model assuming movement of electron's is less predictable
Electron cloud model or
quantum-mechanical model
Atoms of an element with the same numebr of protons but different numbers of neutrons
Isotopes
Elements in Group 8A
Noble Gases
Developed first atomic theory
Dalton
hypothesized that electrons orbit around the nucleus at fixed distances
Bohr's Atomic Model
Electron in the highest energy level
Valence electrons
The element sodium is made up of all atoms with 11 protons. How many protons, electrons, and neutrons are in a sodium-23 atom?
11 protons
11 electrons
12 neutrons
Elements in Group 7A
the halogens