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