Easiest concept to learn: 
Graphing, It was just taking data and graphing it.
Hardest concept to learn:  Metric System, learning the metric system is like trying to learn a different language. It's so different.
Most Important: Metric System, a lot more people and places use the metric system so it could come in handy when we are older.
Concept that might need reviewing: The Metric System, I forgot a lot of it. 

Easiest concept to learn: Physical and Chemical Changes, it was easy to remember what made a change Chemical or Physical.
Hardest concept to learn: Classification Of Matter was not necessarily difficult just not easy to remember what made it was it is.
Most Important: Physical and Chemical Changes, I feel like it is important to know the difference because they are not the same.
Concept that might need reviewing: 
Classifying Matter, I had a hard time remembering the concept itself.

Easiest concept to learn: Periodic Table, there wasn't anything difficult about it really.
Hardest concept to learn: Chemical Reactions, I couldn't get Valence Electrons to really stick, I kept forgetting about them and stuff.
Most Important: The Periodic Table, I think it is very important to know the Periodic table because there are a lot of elements out there and you need to know them.
Concept that might need reviewing: Probably Chemical reactions because I forgot a lot of information on them.