Science; Compounds, Molecules and Atoms?

Okay, so... please correct me if I'm wrong: Elements are made of many/one of the same atom... Molecules do not need to be made of the same atoms/elements.. Molecules are made of atoms? A compound is made of two or more different elements.. therefore, two or more different kinds of atoms? or one kind of... show more Okay, so... please correct me if I'm wrong:

Elements are made of many/one of the same atom...
Molecules do not need to be made of the same atoms/elements..
Molecules are made of atoms?
A compound is made of two or more different elements.. therefore, two or more different kinds of atoms? or one kind of molecule which has different atoms inside it? *confusing*

VALENCY!
Is the combining power of an element and the electrons on the outer shell. These electrons are valence electrons. << is that true? and could I please get a little info on this valency stuff?

Please&Thankyou in advance,
Update: Even a definition of each of these would be highly appreciated.
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