Transcript Element FOlder

NO WHOT WEEK
Warm Up: With your desk partner (1 page
for both)
1. On scratch paper, draw
an atom, label its parts
2. Then…name 5 physical
properties
3. Then Turn it in with both
names
Element Folder
Due Friday at the beginning of class
Rubric!
Mostly looks like
this
http://www.ptable.com/
• Element Square
• What does it all mean?
Atomic Number
(# of protons)
Elemental Symbol
Average Atomic Mass
(# of protons & neutrons added together)
These
are
electron
orbitals,
ignore
these
numbers
How do we find the number of
neutrons in the atom?
Steps:
1. Round the atomic mass
2. Subtract the atomic
number from that number
3. The difference is the
average number of
neutrons
Atomic Number
56
- 26
30
Average Atomic Mass
Element Folder: Day 1
Day 2:
Element Folder
Due Friday at the beginning of class
Warm Up:
1. Look at this Bohr diagrams- which letters
are correct? Which are incorrect?
2. The electrons in the outermost energy level
are called what?
A Bohr diagram for nitrogen.
2
7
3
N
Nitrogen
1
14
Mass Number:
4
A Bohr diagram for neutral
nitrogen atom.
7P
7N
Special Electrons
 Valence Electrons
◦ In the outermost energy level of an atom
◦ Can bond with other atoms
1 valence e-
7 valence e-
What is an ion?
• http://www.youtube.com/watch?v=WWc3k272
3IM
Periodic Table of Bohr Models
• New energy level for each new row (period) on the
table
• Same number of valence electrons for the atoms in
each column (group)
• Number of valence electrons = periodic column #
Two is cool! Eight is great!
Everything wants a sense of
fulfillment- even atoms
To get this- Take charge!
Ions are charged particles due to
the gain or loss of electrons
Bohr and the periodic table
P is the elemental symbol for Phosphorus.
1. In which group is Phosphorus found?
2. In which period is Phosphorus found?
Bohr and the periodic table
P is the elemental symbol for Phosphorus.
Phosphorus has 5 valence electrons.
How many electrons to be happy?
If it received 3 more it would be fulfilled!
And very HAPPY!
Bohr and the periodic table
What is the charge of this Phosphorus ion?
3-
Day 3:
Element Folder
Due Friday at the beginning of class
Warm Up:
1. Look at your data from the physical properties lab
2. What did the compounds with HIGH melting points
have in common
3. What did the compounds with LOW melting points
have in common
Molecules
• Where to find molecules
your element makes:
ptable.com
• Click compounds tab
• Click your element
• Choose 1 from list
Bonding Vocabulary… to help you
determine if your compound is
ionic, covalent, or something else
• Electronegativity: Ability of atom to gain
electrons
• Relative measurement – no units
• High (up to 4) – tends to gain electrons (right side of
periodic table)
• Low (down to 0) – tends to lose electrons (left side
of periodic table)
• Ionic Bond: Forms between atoms of metals &
nonmetals
• Electronegativity difference >1.9, it’s ionic bond
A look at the Process
Low
electronegativity
Na gives up e-
High
electronegativity Cl
takes e-
Becomes + Charged
Becomes - Charged
[Na]+
[ Cl ]-
What Happens to Ions?
Opposites Attract!
[Na]+
Note: Lewis
Diagrams next
- to
each other
represents formula
unit of NaCl
[ Cl ]
Covalent: non-metals
electronegativity difference = 0
• Elements in bond have same
electronegativity
• Usually the same kind of atoms
• Ex: Cl2, O2, N2
Each Cl
needs one
electron;
Neither will
give one up;
They SHARE
• Look at Cl:
This atom
uses these
electrons
to follow
the octet
rule
And so
does this
one.
Formula: Cl2
Covalent: non-metals
electronegativity difference = 0 Each Cl needs
• Elements in bond have same electronegativity
one electron;
Neither will
give one up;
• Usually the same kind of atoms
• Ex: Cl2, O2, N2
• Look at Cl:
They SHARE
This atom
uses these
electrons to
follow the
octet rule
And so does
this one.
Formula: Cl2
Polar Covalent
• Atoms in bond have slightly different electronegativity
• Electronegativity difference > 1.9:
• Electronegativity difference < 1.9:
• Electronegativity difference = 0:
ionic bond
polar covalent bond
covalent bond
• Shared electron stays with more electronegative element
more of the time
Polar Covalent Example
• Hydrogen Chloride: HCl
H
Cl
2.1
3.2
• H: electronegativity = 2.1
• Cl: electronegativity = 3.2
• Cl attracts shared electrons more
than H
• Dipole forms because Cl becomes
more negative and H is less
negative