Everything known in Science (Universe) Matter has mass ( measure of how much) has volume (takes up space) Energy cause change / do work

Matter - always built from Atoms Atoms – smallest complete units of matter Atoms - made of 3 smaller (subatomic) particles Protons Neutrons Electrons

Nucleus = center

Helium atom

Periodic table of the Elements Different atoms become the foundation for different elements

Periodic table of Elements? Element = a pure collection of the exact same type of atoms. Elements or Atoms? Pure = only one type of atom is present Because they are built on the smallest whole unit of matter…the atom… Elements cannot be broken down into different simpler substances !!!!

What is the symbol that represents the element Carbon? The capital letter ‘C’ What is the symbol that represents the element Helium? The capital letter ‘H’ followed by a lowercase ‘e’ The symbol for an element will ALWAYS START WITH A CAPITAL letter and… it will have only ONE capital letter…(it may have a lower case letter).

Is this a model for an Element? No…it’s got more than one type of atom

This is the compound - H 2 O Compounds = two or more elements that are chemically bonded together Because the different types atoms are chemically bonded… Compounds are NOT MIXTURES! The properties of a compound are different than those of the element from with they are formed. EX: Hydrogen an explosive gas…Oxygen a clear gas that supports combustion. H 2 O – clear liquid that puts out fire!

This model for has lines to help show that the elements H and O are chemically bonded together. Think of these bonds as the energy bonds required to hold the elements together. Compounds have more than one element chemically bonded by energy… so…how many capital letters must be in their formula???? H2OH2O NaClNaCl NaCl TWO OR MORE ! H2OH2O C 12 H 22 O 11

Can a compound be pure? Sure…as long as only that compound is present. If it’s all H 2 O…it’s pure

Elements are represented by SYMBOLS. They always Start w/capital & have only one capital. EX: O = Oxygen Fe = Iron Because they are made from one type of atom…Elements cannot be broken down into different simpler substances !!!! Compounds are represented by FORMULAS The formula is a recipe that shows what elements are chemically bonded together in the compound. EX: H 2 O = 2 Hydrogen bonded with 1 oxygen CO 2 = 1 Carbon bonded with 2 oxygen. Because they are made from two or more types of atoms….compound can be broken into simpler substances. Summary – Element vs. Compound

Which is an element? Which is a compound? AB A = Element One type of atom B = Compound More than one type of element

Which is pure? AB Both !

Are these containers pure? A B NO !