Download Unit 3 Study Guide

Unit 3 Study Guide
Test Date: _______________________

Smallest part of an element that can still be classified as that element:
o Atom

Mass does not change. Weight changes depending on your location (gravity).

Do you remember how to read a tile on the Periodic Table? Which number represents the
atomic number? Atomic mass?

Examples of a physical property:
o Density
o Solubility (dissolving)
o Malleability
o Ductility

Examples of a chemical change:
o Rusting
o Producing a new gas
o Burning
o Cooking/baking
o Tarnishing
o Photosynthesis (plant growth)
o Reactive

Elements – made up of ONE type of atom
o Examples: Na (Sodium), C (Carbon), H (Hydrogen), Al (Aluminum)

Compounds/Molecules – two or more atoms CHEMICALLY combined
o Examples: NaCl (table salt), CO2 (carbon dioxide), H2O (water), H2O2 (hydrogen peroxide)

Mixtures – two or more substances PHYSICALLY combined
o Examples: soil, salt and sand, sugar dissolved in water
o Heterogeneous – a mixture that is NOT the same throughout
o Homogeneous – a mixture that IS the same throughout

Solid – particles are close together and vibrate slightly

Liquid – particles are close together but are able to slide past one another

Gas – particles are far apart and move around freely

Plasma – behaves like a gas; charged particles move around freely
o Examples: lightning, stars, Northern Lights

There are currently 118 known elements on the Periodic Table.