Earth Chemistry
• Matter - is anything that has mass and takes up space• The amount of matter in an
object is called mass• All matter has measurable
properties which helps identify it
• Physical properties• Properties that can be
observed without changing the composition of the matter
• Examples: Color, hardness, state of matter, density
• Chemical properties• Properties that describe how
matter reacts to other substances
• Example: flammable
Matter has 4 Phases/States• Solid – particles are packed
together and only vibrate• Liquid – particles are less
packed together than solids and slide past each other
• Gas – particles are far apart and move quickly
• Plasma – similar in properties to a gas but can conduct electricity in certain conditions
• Elements•Are substance that
cannot be broken down into simpler substances by chemical means
•Each element is made of its on atom
•Are represented by a symbol
•They are organized into the periodic table
Periodic Table• It has a series of boxes that
represent each element• The parts in each box
• Atomic Number – at the top•Represents the number of protons
• Symbol – represent the name of the element
• Atomic mass – at the bottom•Represent the total number of protons plus neutrons
Oxygen
8
O15.999
Atomic Number
Atomic Mass
Symbol
Periodic Table Set Up• Rows
• Go across• The atomic number increases
by one each time you go across
• Columns (called families or groups)• Go down• Each group has a name• All elements in the same group
have the same number of valence electrons so they react similarly
• As you go down they get larger
• Atoms – the smallest unit of an element (made of mostly empty space)
• Two parts:• Nucleus
• Protons:− Have a positive charge − Mass = ~ 1 amu
• Neutrons:− No charge − Mass = ~ 1 amu
• Electron cloud• Electron:
− Have a negative charge − Mass = 9.1 x 10-31 − Force of attracted to the protons in
the nucleus hold them in place
• An elements protons can’t change or it is not the same element
• But it can change neutrons or electrons• Neutral – have equal number of
all particles• Isotopes – a different number of
neutrons • Changes the mass
• Ions – have a different number of electrons
• If extra – they have a negative charge• If fewer – they have a positive change
• Valence electrons – the electrons that are in the outer shell of an atom
• They determine:• The atoms properties• What atoms they can bond with
• The goal is to have the outer shell full (eight electron in outer shell)
• If the outer shell is full it’s called inert (or inactive) – won’t react
• When atoms bond it is chemically • Forms a compounds• Compounds have properties are
different than the elements in it• Example: Water
Representing compounds• Chemical formulas – a
combination of letters and numbers that the makeup of the compound
• Include:• Symbols • Subscripts = little numbers to
the lower right• Tells the number of atoms of that
element
• Coefficient – large number in the front
• Tells the number of molecules
Example of Chemical Formula
C6H12O6
4C6H12O6
• To show how substance react with each other we use a chemical equation• Parts of the equation
•Reactants – on the right side of the arrow (starting materials)
•Products – on the left side of the arrow (what is made)
• All equations must have the number of each type of atom on both sides of the equation
Example of Reaction
2 Ag + S Ag2S
How are the substance held together?
• Chemical bonds – forces that hold together atoms in a molecule
• Bonds can occur if electrons from different atoms are shared or transferred
Name of Bonds• Ionic – transfer electrons•Covalent – share
electrons
Ionic Verses Covalent BondsIonic Verses Covalent Bonds
Factors Affecting Reaction Factors Affecting Reaction RatesRates• Temperature• Surface area/Particle size• Concentration of solution• Pressure• Catalysts• Inhibitors
Increasing Surface AreaIncreasing Surface Area
