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:
C:
H:
N:
Oxygen
Carbon
Hydrogen
Nitrogen
How do I find the Neutrons?
Element
Na
Cl
Mg
Ne
Ag
Br
Bonus:
Ds
Protons
Electrons
Neutrons
Element
Protons
Electrons
Neutrons
Na
Cl
Mg
Ne
Ag
Br
Bonus:
Ds
11
17
12
10
47
35
110
11
17
12
10
47
35
110
12
18
12
10
61
45
171
Rules for writing element
symbols
• Must print
• 1st letter capitalized
• 2nd letter lower case
Why?
Ex. CO vs. Co
Carbon& Oxygen vs Cobalt
Atom
Smallest 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
Electron cloud
or Shell or Level
Electron (e-)
• Proton (p+)
• Neutron (n)
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
3
Li
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 Gases
• Non-reactive
• Full outer shell
Famous Families
Alkali Metals
• Highly Reactive with water and the
Halogens
• Reactivity increases as you move down the
group
•1 electron in
outer shell
Demos
Na
Famous Families
Halogens
• Highly Reactive with alkali metals
•Missing 1
electron in
outer shell
Noble
Gases
Halogens
Alkali Metals
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
element
molecule
compound
atom
molecule
• Atoms are the building blocks of matter.
• Each element is made of the same kind of atom.
•A molecule is made of two or more different kinds of
elements that are chemically bonded.
•Each compound is made of the same kind of molecule.
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
Counting Atoms:
A small number, below and to the right
of the element symbol, is called a
subscript# = # of atoms
C6H12O6
6 C atoms + 12 H atoms + 6 O atoms = 24 total atoms
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
CuSO4 =6 atoms
6 x 2 =12 total atoms
3 Elements
Parentheses 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