Kristina Ravalo
Mr.Doktor
Chemistry 11
Block E
March. 23, 2010

Q: isotopes are used for in medicine? A:they give off radiation

ATOMS & IONS
• Atoms are electrically neutral
• # of protons= # of electrons
• Ions have different number of protons and electrons
• Ions can be either positive (lost e-) or negative (extre e-)
• Metals will be positive and non metals will be negative
• In order for something to be positive, it needs to lose electrons.
• If it’s negative it’s gaining electrons
• Cation= positive ion
• Anion= negative ion

Examples:
Determine how many electrons each of the ions have. What type of ion are they? (cation or anion)?
Ca2+  lose 2e- it is a CATION
Ag+ lose 1e- it is a CATION
F-  gains 1e- it is an ANION
H- gains an e- it is an ANION
H+ loses an e- it is a CATION
N3-  gains 3e- it is an ANION

Examples:
Determine how many protons, neutrons and electrons the following substances have.
Protons: same number as atomic number
Neutrons: atomic mass minus protons
Electrons: atomic number and protons

76AS3- protons: 33
 Neutrons: 43
 Electrons: 36
201 AU+  protons: 79
 Neutrons: 122
 Electrons: 78
56FE 3+ protons: 26
Neutrons: 30
Electrons: 23


BOHR DIAGRAM FOR IONS
• Draw the energy level bohr diagram for the following ions:
-Ca 2+
8e-
8e-
2e-
Ca

-Li+
4-
2-
Li

F-
8-
2-

O2-
8e-
8e-
2e-

P3-
8e-
8e-
2e-

CHEMICAL BONDS
• A bond is an electrostatic attraction between particles
• Bonds occur as elements try to achieve noble gas electron configuration
- Noble gases (usually) do not form compounds or bonds
- In noble gases the outermost energy level have stable octets
• Metals lose electrons (oxidize)
• Non metals gain electrons (reduced)




LEWIS DOT STRUCTURE
• Atoms can be represented by dot diagrams
- - Dots represent electrons
- Only valence level electrons are shown
• Write the atomic symbol for the atom
-This represents the nucleus and filled inner electron levels
• One dot is used to represent outer energy level electrons
-One e- is placed in each orbital before any pairing occurs
- Beginning with the 5th e-, pairing can occur up to a maximum of 8e-

Ex. Draw the lewis dot diagram for the following atoms:
- Nitrogen
- Fluorine
- Oxygen
- Calcium
- Lithium
- Hydrogen



LEWIS DOT STRUCTURE
• Atoms can be represented by dot diagrams
- - Dots represent electrons
- Only valence level electrons are shown
• Write the atomic symbol for the atom
-This represents the nucleus and filled inner electron levels
• One dot is used to represent outer energy level electrons
-One e- is placed in each orbital before any pairing occurs
- Beginning with the 5th e-, pairing can occur up to a maximum of 8e-

Ex. Draw the lewis dot diagram for the following atoms:
- Nitrogen
- Fluorine
- Oxygen
- Calcium
- Lithium
- Hydrogen

IONIC BONDS
• Electrons are transferred from metal to nonmetal
- No dots are shown on metal
• ‘charged’ species is written in brackets
• Example: sodium chloride
Na Cl

EX: DRAW THE LEWIS DOT DIAGRAM FOR
- LITHIUM FLUORIDE
- CALCIUM CHLORIDE