Catalyst – February 3-1, 2011
WAY BACK WEDNESDAY!
1.
Describe what you know about
light. Write down as many things
as you can think of.
Today’s Agenda
Catalyst
 Group Challenge!
 Bohr Model Review
 Periodic Table Basics: Notes and Work Time
 Exit Question

HOMEWORK: ATOMIC TRENDS
WORKSHEET, READ 11.7-11.11
Today’s Objectives
SWBAT draw Bohr Models for the
first 20 elements like pros!
 SWBAT describe/identify the main
regions and families of the periodic
table.

GROUP REVIEW CHALLENGE
(5 MINUTES)
Navigating the Periodic Table
Atomic Number
(small whole number)
Element Symbol
(letters)
Atomic Mass
(big decimal number)
Atomic Number is an Element’s ID Number

Like your social security number or a
professional athlete’s jersey number, the
atomic number of an element identifies
that element
Find the atomic number of this element
Find the atomic number of this element
Bohr Models of Atoms

Key Point #1: A
Bohr model depicts
an atom as a small,
positively charged
nucleus surrounded
by electrons that
travel in circular
orbits around the
nucleus
16 p+
16 no
Sulfur: 16 protons
16 neutrons
16 electrons
Energy Levels

Key Point #2: Energy levels (or shells)
are paths around the nucleus where
electrons travel
Energy
levels are also known as orbits
Energy increases as you move further
from the nucleus
Valence Electrons

Key Point #3: Valence electrons
(ve-) are electrons in the outermost
energy level
They
are the furthest from the nucleus
An atom could have 1 ve-, 2 ve-, 3
ve-, etc.
Steps to Making a Bohr Model
1.
2.
3.
4.
5.
6.
Determine the number protons, neutrons, and
electrons in the atom
Draw the nucleus (circle) with # p+ and # no inside
Draw the first energy level (circle around nucleus)
and draw up to 2 dots (electrons)
If needed, draw second energy level (second circle)
and draw up to 8 dots (electrons)
If needed, draw third energy level (third circle)
and draw up to 8 dots (electrons)
If needed, draw fourth energy level (fourth circle)
and draw up to 18 dots (electrons)
How did scientists like Bohr and Schrodinger
develop modern atomic theory?



Electromagnetic radiation – a form of energy
transferred from one place to another in the form
of WAVES
Photons – a stream of tiny packets of energy,
PARTICLES
Emission of Energy by Atoms (section 11.3)
 When
atoms receive energy, they become excited and
can release this energy by emitting light in the form of
a photon
The Energy Levels of Hydrogen
(Section 11.4)




Hydrogen atoms are excited with energy
They emit photons of light (to release this energy)
They only release certain types of photons, which
corresponds to discrete/quantized energy values
ENERGY LEVELS!!!
Bohr vs. Schrodinger

Bohr created a model that agrees with the
hydrogen emission data
 Circular

orbits
Schrodinger created a model based on the waveparticle nature of light
 Orbitals
are nothing like orbits
 Wave mechanical or quantum model of the atom
CHECK OVER YOUR
BOHR MODELS
DO YOU HAVE ANY
QUESTIONS???
PERIODIC TABLE
NOTES
The Periodic Table
Key Point #1: The periodic table organizes
the elements into many different groups
based on physical and chemical properties.

We will learn about the major ways to group the
elements – by…
 Family
 Metals/Metalloids/Nonmetals
 Valence
Electrons
 Atomic Radius (Size)
What does PERIODIC mean?
Key Point #2: Periodic means that there
is some kind of pattern.
In the Periodic Table, there are numerous
patterns
 What about in regular life? How could you
group the following items in different ways?

The Evolution of the Periodic Table
Just like atomic theory, the Periodic
Table also has a long history
 In the late 1790s, French scientist
Antoine Lavoisier compiled a list of
elements known at that time - only 23!
 In the 1800s, scientists began
discovering a ton of elements - up to
70!

Evolution Continued
New elements meant new data!
Scientists needed a way to organize
everything!
John Newlands (1860s)
Arranged the Periodic
Table by increasing
ATOMIC MASS
 Noticed patterns based
on physical and
chemical properties repeated every 8th
element
 Law of Octaves

Newland’s Periodic Table
Law of Octaves
Mendeleev (1869)

Arranged elements by
increasing ATOMIC
MASS into columns based
on chemical and physical
properties
 Left spaces for
undiscovered elements
 First to publish table
Mendeleev’s Periodic Table
EMPTY SPACES!
Mosely (1913)
Arranged elements
by increasing
ATOMIC NUMBER
 Some of Mendeleev’s
elements in the wrong
order
 Periodic Law

Our Periodic Table – Thanks to Mosely
Periodic Law

Periodic Law is the statement that there
is a periodic (patterned) repetition of
chemical and physical properties of
the elements when they are arranged
in increasing atomic number
Basic Terms to Know
Write these in your notes to remember!
Period – horizontal rows on
periodic table
 Family/Group – vertical rows on
periodic table

PERIODIC TABLE
WHITEBOARDS!

Periodic Table Whiteboards!
1.
2.
3.
Draw the staircase on the periodic
table.
Label the Metals, Nonmetals, and
Metalloids.
Circle the atom with ZERO neutrons.
ERASE!
Periodic Table Whiteboards!
1.
2.
3.
4.
5.
Label the Alkali Metal family.
Label the Noble Gas family.
Put a box around the Transition Metals.
Circle 3 Lanthanides.
Put a triangle around a halogen.
ERASE!
Metals, Metalloids, and Nonmetals
Major
Families
Alkali Metals
Noble Gases
Halogens
Alkaline Earth Metals
H
He
Be
Transition Metals
Lanthanides Ce
Actininides
Th
B
C
N
O F
STUDY SECTION 3.8 TO HELP
YOU REMEMBER THIS INFO!
Alkali Metals
Alkali metals are very reactive – even
with water!
Sodium + Water  EXPLOSION!
Alkaline Earth Metals
Alkaline Earth metals are also very reactive
 Shiny solids that are harder than Alkali
metals
 Alkaline Earth Metal Spotlight: CALCIUM

 Calcium
is essential for human life, especially in
maintaining bones and teeth
 Found widely in nature combined with oxygen
 Abrasives in toothpaste and emery boards

Magnesium Demo!
Boron’s Group

Gallium is a silver metal that literally melts in your
hand!
Don’t try this
yourself!
Carbon’s Group

Carbon is one of the most important elements on
Earth!
 There
is a whole branch of chemistry dedicated to
studying carbon – ORGANIC CHEMISTRY!
 If you are a science major in college, you will most likely
take Organic

Silicon is the second most abundant element on
Earth!
 Use
in computer chips and solar cells
 Found in quartz, sand, and glass
Nitrogen’s Group
Metals, nonmetals, and metalloids!
 Nitrogen, which you breathe, can form some
of the most explosive compounds known to
man
 Arsenic is a toxic substance that was used to
treat some illnesses back in the day
 Bismuth is used in fire sprinklers

Oxygen’s Group

Oxygen
 We
must breathe oxygen to survive…so it’s
pretty important
 Reacts with some of the noble gases

Sulfur
 Hydrogen

sulfide smells like rotten egg
Selenium
 Used
in solar panels because it can convert light
into energy
Halogens (Fluorine’s Group)


Fluorine (really fluoride)
is added to toothpaste
Chlorine gas is a deathly
green gas that was first
used as a form of
chemical WARFARE in
WWII
Noble Gases (Helium’s Group)

Noble gases do not react with other elements
very often – they are already “happy”
 They
can be called “inert” because they don’t
react
Neon is used in neon lights
 Helium Voice!

Transition Metals
Conduct electricity
 Can form different ions (We’ll learn more
about ions later!)
 Many found in nature – found all over the
world
 Uses

 Found
in alloys, wires, plastics, etc.
 Your body needs trace (small) amounts many of
them
PERIODIC TABLE BASICS
WORKSHEET
Exit Question
1.
2.
Why is the periodic table called
the “periodic” table?
List 3 groups on the periodic table.
HOMEWORK: ATOMIC TRENDS
WORKSHEET, READ 11.7-11.11