Chemistry 101

Elements are completely pure.

• All Matter is made up of Elements

• They are only made of one type of ATOM

HELIUM ATOM

Elements make up all living things.

O: Oxygen

C: Carbon

H: Hydrogen

N: Nitrogen

How do I find the Neutrons?

Element Protons Electrons Neutrons

Na

Cl

Mg

Ne

Ag

Br

Bonus:Ds

Element Protons Electrons Neutrons

Na 11 11 12

Cl 17 17 18

Mg 12 12 12

Ne 10 10 10

Ag 47 47 61

Br 35 35 45

Bonus:Ds

110 110 171

Rules for writing element symbols

• Must print• 1st letter capitalized• 2nd letter lower case

Why?

Ex. CO vs. CoCarbon& Oxygen vs Cobalt

AtomSmallest particle of an element

that still has the characteristics of that element

Atom of Sodium

                                     

      Actual photograph of atoms of germanium in an ink-blot.

Structure of an atom

• Proton (p+)• Neutron (n)

Electron cloudor Shell or LevelElectron (e-)

Electron energy levels• Are regions where electrons travel

around the nucleus .• Each energy level can only hold a

certain number of electrons• 1st Shell = 2 electrons• 2nd Shell = 8 electrons• 3rd Shell = 8 electrons

Li3

Groups/Families• The elements in a column are called a group.

• Groups are also known as families.

• Elements in a group have similar characteristics.

• The OUTER SHELL = VALENCE SHELL

ADD this sentence

Periods• Each horizontal row is called a period.

• A period contains a series of different type of elements from different family.

• They represent the # of SHELLS.

ADD this sentence

Why the Table Works?

• Elements have different numbers of outer (valence) electrons

• The number of (valence) electrons determines whether it gives up, shares, or accepts other electrons.

• That number of valence electrons an element has increases from left to right known as a period!

Famous Families

Noble GasesNoble Gases• Non-reactive

• Full outer shell

Famous FamiliesAlkali Metals• Highly Reactive with water and the

Halogens

• Reactivity increases as you move down the group

Demos

•1 electron in outer shell

Na

Famous Families

Halogens• Highly Reactive with alkali metals

•Missing 1 electron in outer shell

Alkali Metals Halogens

Noble Gases

On your big periodic Table:1.Circle and label the three groups above.2.Star the metalloids which are in yellow

Building Blocks of Matter

• Atoms are the building blocks of matter.

molecule

compound

moleculeelement

molecules

•Each compound is made of the same kind of molecule.

•A molecule is made of two or more different kinds of elements that are chemically bonded.

• Each element is made of the same kind of atom.

atom

Compound• Compounds are pure substances

• Only made of one type of molecule!

Example: Sodium Chloride…

Element• Elements are pure substances

• Only made of one type of atom!

Example: Sodium

The Compound: Sodium Chloride

Element vs Compound Stations

Compounds Element

Counting Atoms in a Molecule

Counting Elements:

Every Capital letter is the beginning of a new element in the formula.

  Capital letter = New element

NaCl = 2 elements: Na & Cl

6 C atoms + 12 H atoms + 6 O atoms = 24 total atoms

Counting Atoms:

A small number, below and to the right of the element symbol, is called a

subscript# = # of atoms 

CC66HH1212OO66

Counting Total Atoms in Compounds:

A large number at the beginning of a formula signals that there are two of that molecule.

1. Count the total atoms after the #2

2. Then multiply the group by 2

2 CuSO4

3 Elements6 x 2 =12 total atoms

CuSO4 =6 atoms

Parentheses and subscriptsParentheses and subscripts

1. Add the inside of (parentheses) first.

2. Multiply the ( ) by the subscript.

3. Add the other atoms to your answer

NaH(CO3)4

CO3 + CO3 + CO3 + CO3

4 Elements

18 Total Atoms

Building Molecules Lab

Why Chemical Reactions Occur…

Three things to remember:

1. Atoms want to be stable!

2. Atoms with full outer levels are stable

3. Atoms will do anything to become stable!

Chemical Reaction Example

2 types of Chemical “Bonding”

• Covalent bonding: atoms share electrons– Ex. Oxygen (Oxygen bonds with oxygen)

•Ionic: atoms gain or lose an electron –Ex. Chlorine needs one electron and sodium has one extra to give.–This changes their charge and makes NaCl