Notes

Compounds:
Some matter around you is uncombined elements (copper, oxygen, sulfur) these 3 elements combine chemically to form a compound when conditions are right.

Formulas:
Chemical formula tells what elements a compound contains and the exact number of the atoms of each element in a unit of that compound
Subscript tells you how many atoms of an element. Symbol has no subscript unit only has 1 element. A unit of H2O contains 2 hydrogen atoms and 1 oxygen atom

Atomic stability:
The electric forces between oppositely charged electrons and protons hold atoms and molecules together, and thus are the forces that cause compounds to form.
Atoms of noble gases are unusually stable
Compounds of these atoms rarely for because they are almost always less stable than the original atoms

Unique noble gases:
To understand the stability of the noble gases, it is helpful to look at electron dot diagrams. (He has 2 others have 8)
They show only the electrons in the outer energy level of an atom.

Chemical stability:
The noble gases are stable because each energy level is full

Outer levels – getting their fill:
They combine with other atoms that also have partially complete outer energy levels to become stable again or lose its outer electrons as a result each achieves stability.
Sodium + Chlorine = Sodium Chloride

Stability is reached:
When atoms gain, lose, or share electrons, an attraction forms between the atoms, pulling them together to form a compound. Causes them to have different charges positive + negative attract

Section 2
Gain or loss of electrons:
The positive and negative charges are not balanced
Atoms lose or gain electrons to meet standards
Some of the most common compounds are made by the loss and gain of just