Warm Up
Which is more reactive, Potassium or Rubidium?
Which is more reactive, Chlorine or Iodine?
Plan for the Day
 Meet the Halogens (Reading)
 Lab Safety & Procedure
 Complete Lab #4: All in the Family
 Homework? …practice test and
study guide!
Meet the Halogen Family
•
•
•
•
•
Nonmetals
Reactive
F2 and Cl2 are gases
Br2 is a liquid
I2 is a solid
Reading the Background
 Do: Read and highlight main ideas.
 Put: Mark Text and Annotate
 Finish By: 5 minutes.
 When done: Read the Pre-lab
questions #2 and #3 and answer
them in the margin.
Learning Target
I can experimentally
determine the
similarities and
differences in the
chemical properties
of the halogens.
Read Safety Precautions
Waste Disposal
Visit the Disposal Stations in the
Vent Hood
Lab #3: Meet the Halogens
 Do: Follow the procedure. Check off
each step as it is completed.
 Put: observations in the Data Table.
 Finish By: 30 minutes.
 When done: Clean your lab station &
begin answering the Post Lab
Questions #1 to #12.
Entry Ticket
• Annotated Background
• Data Table
• Post Lab Questions
Halogen Activity Series…
Cornell Notes
 Title: Periodic Trends of Metals and Halogens
EQ: Why do the reactivity trends exist?
What do you
see?
Can you
explain why…
ATOMIC SIZE DECREASES?
Can you
explain why…
ATOMIC SIZE DECREASES
Because as more protons are
added to the nucleus and more
electrons are added to shells,
they attract each other.
This happens periodically…
Can you
explain why…
ATOMIC SIZE DECREASES
It also means that the relative
strength (effective nuclear
charge) increases from L  R.
Reactivity  Atomic Structure
 Alkali Metals and Alkali Earth Metals
• Atomic Radius increases down the group
because more electron shells added
• Valence electrons are shielded from the pull of
the nucleus as more shells added and are
removed more easily
More shells
Reactivity  Atomic Structure
Halogens
• Atomic Radius increases
down the group because
more electron shells added
• Fluorine is the most reactive
because it has a high
nuclear charge, smallest
radius, and less shells of
electrons and therefore can
attract other element’s
electrons to itself more
easily.
Reactivity  Atomic Structure
What do you
see?
Remember this?
You need to know it
Practice Test Resources
 Learning Target Page
(notebook)
 Periodic Properties of Elements
Lab
 Create-a-Table Activity
 Periodic Properties of Metals
Lab
 Meet the Halogens Lab
 Today’s Notes w/ Repetition
Reactivity Trend
(Put Under Color Coded P.T.)
 Elements in each column have the same
number of valence electrons (outer shell
electrons), which determine chemical
properties. SO…
 Elements in the same group (vertical
column) tend to react in similar ways.
AND…
 Within a group there are reactivity trends
from most reactive to least reactive.
INCREASES
Atomic Radius
DECREASES
But WHY?
Atomic Radius
 Why does this trend exist?
 “Atomic radius decreases from
left to right in a period
because…”
 “Atomic radius increases from
top to bottom because…”
Atomic Radius
Because you are adding more and more protons,
which pull the electrons in their orbitals closer and
closer. This causes the radius to shrink.
DECREASES
Because there
are more and
more energy
levels –
electrons repel
each other and
can’t be in the
same space.
This causes the
radius to grow.
INCREASES
Atomic Radius
Ionization Energy
I.E. is the amount of energy it
takes to remove a valence
electron
But WHY?
DECREASES
INCREASES
Ionization Energy
 Why does this trend exist?
 “Ionization energy increases
from left to right in a period
because…”
 “Ionization energy decreases
from top to bottom because…”
Electronegativity
Electronegativity is a term used to
describe the tendency of a nucleus
to attract electrons toward itself.
But WHY?
DECREASES
INCREASES
Electronegativity
 Why does this trend exist?
 Electronegativity increases from left
to right because…
 Electronegativity decreases from
top to bottom because…
Last Slide! 
Tape in the small periodic table
with the trends next to your
notes.