Notes

I. Atomic Theory and Structure
Plum-Pudding Theory
It Introduced the notion of the atom as a non-inert, divisible mass.

Rutherford Gold Foil Experiment
Importance that proved that there's something heavier than alpha particles. It concluded that matter isn't uniform.
1. There's a small core called a nucleus
2. Most of the volume is empty space.
3.the atom is electrically neutral b/c there's protons and electrons

James CHadwick
He discovered neutrons.

Subatomic Particles
Protons and Neutrons have the same mass.

Elements are defined by their numbers of protons.
Atomic Number is given the symbol Z
Atoms with the same number of protons but a different number of neutrons are called isotopes.

II.
During chemical change, however, atoms can lose or gain electron's and become charged particles called ions.
Positively Charged cations
Negatively Charged - anions

Mendeleev summarized these observations in the periodic law-
-when the elements are arranged in order of increasing there's certain properties that reoccur.

Perodic
MEtal - Readily loses electrons
Non_metals- readily gains electrons
MEtalloids- they do both gain and lose electrons.
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