all matter is made up of individual particles called atoms, which cannot be divided.
noticed that the ratio of the masses of elements in a compound is always the same.
provided evidence that atoms are made of even smaller particles
Plum Pudding Model or the Chocolate Chip Ice Cream Model
Discovered the Nucleus
dense, positively charged mass located in the center of the atom.
protons, electrons, and neutrons
positively charged subatomic particle found in the nucleus of the atom
a negatively charged subatomic particle found in the space outside the nucleus
a neutral subatomic particle found in the nucleus of the atom
Protons and Neutrons
have a similar mass
is equal to the number of protons in an element
is the sum of the protons and neutrons in the nucleus of an atom
Number of Neutrons
Equals the Mass Number minus the Atomic Number
atoms of the same element that have differnt numbers of neutrons and different mass numbers
the atom is like the solar system and the planets orbiting the sun
The possible energies that electrons in an atom can have.
energy is absorbed
Electrons move up an energy level
energy is released
Electrons move down an energy level
most likely locations for electrons in an atom
region of space around the nuclues where an electron is likely to be found
when all electron in an atom have the lowest possible energies
The most stable electron configuration