Unit 1: Structure and Properties of Matter

any substance that has a mass and takes up space.

• mass
• matter

molecules are very loosely packed and bounce around (high energy)

• solid
• liquid
• gas

elements that run horizontally on the periodic table

• period
• group

change: when matter changes into a new substance and cannot change back into its original form

• chemical
• physical

molecules are tightly packed and vibrate in place

• solid
• liquid
• gas

the basic particles or “building blocks” of matter

• atoms
• liquid

change: when matter changes only its appearance and keeps its original composition

• chemical
• physical

molecules are loosely packed and slide past each other (still touch!)

• solid
• liquid
• gas

elements that run vertically on the periodic table

• period
• group

a pure substance that cannot be broken down

• element
• group