What does polar molecules mean? is it charged molecules? does non polar mean that it is not charged?

Polarity is about PARTIAL charges. There is no real charge involved. For example water (H2O) is a polar molecule, because O has a stronger electronegativity than H (that means O attracts electrons stronger than H). Because of this attraction the electrons are often next to the O and so we can say that O has a negative partial charge and both H's has a positive partial charge. 

Non polar means no partial charged.

I hope I could help a bit (and sorry for the bad english)

The arrangement or geometry of the atoms in some molecules is such that one end of the molecule has a positive electrical charge and the other side has a negative charge. If this is the case, the molecule is called a polar molecule, meaning that it has electrical poles. Otherwise, it is called a non-polar molecule.

Abbreviated as mg-25.

Maybe you should get some from your teacher and learn more so you can get your grades up and maybe study a bit more