Chapter 5
Atomic Structure and The Periodic Table
Unit 2
 For Advanced Chemistry…
 This starts Unit 2, which will cover Chapter 5
and Chapter 28.
 Unit 3 will cover Chapters 13 and 14 for those
who like planning ahead.
 For Chemistry…
 You are going to do Chapter 5 totally, but
only selected topics in Chapters 28, 13, and 14
Objective A
http://sunsite.berkeley.edu/CalHistory/photos-large/seaborg.big.jpg
Glenn T. Seaborg
Discovered Plutonium
in 1940; won Nobel
Prize in 1951; had
dinner with Mr.
Schwartz in 1981;
element 106 named in
his honor in 1997 (Sg);
died 1999.
 A tour down memory lane from
about 400 BC to the early 1900s…
 For a quick recap on a lot of the
amazingly important discoveries
that brought chemistry from the
land of con-men practicing mere
magic tricks to the Central Science
that it has become, see…
 Chemical History PowerPoint,
available in Unit 2 on the website.
Objective B: Just how
small is an atom?
http://imagecache5.art.com/p/LRG/6/667/USYC000Z/fedex-field--washington-d-c-.jpg
 Has anyone been to a
professional football
stadium or a major college
football stadium?
So then, most of the atom is
just “empty space.”
 If the nucleus of an atom
was the size of a marble,
sitting at the 50 yard line, the
electrons would be about the
size of really little gnats
(bugs) whizzing around the
top rows of the upper deck.
Objective B: Just how
small is an atom?
http://kara.allthingsd.com/files/2009/04/penny.jpeg
 Let’s use a penny as an example (picture, in
slide show, is approximately life-size). A
penny, if made of pure Cu (copper) would
have 2.4 x 1022 atoms. That’s
24,000,000,000,000,000,000,000 atoms, btw.
Approx. 1 cm from
arrow to arrow (in
slide show mode)
 If you lined up 100,000,000 atoms, they
would make up a line of approximately 1
cm. So, 2.4 x 1022 atoms, if lined up would
make a line that was approximately 2.4 x 109
KILOMETERS long.
How far is that?
http://stardate.org/images/gallery/sun5.jpg
http://1.bp.blogspot.com/_ClzU8TjA_0/SYQUNjRgeRI/AAAAAAAAAAU/kcQOn18_eP4/s320/EarthBlueMarbleWestTerra.jpg
 2.4 x 109 KILOMETERS is 8 trips from
the Earth to the Sun and back.
 By the way, it takes just over 25 pennies
(25.08) to make a mole of Cu. That’s 63.5
grams of pennies.
 Scanning tunneling microscopes are
capable of seeing the surface of
individual atoms. This is a relatively
new development, within the past 20
years or so. Those didn’t exist when I
was in high school or college.
Angstoms (Å)
http://intro.chem.okstate.edu/1314F00/Lecture/Chapter7/ATRADIID.DIR_PICT0003.gif

Even the largest atoms are very small. The diameter of a uranium atom is only about
0.345 nanometers.

A special unit is sometimes used to describe atomic dimensions, such as atomic radius
or atomic diameter. Note the trend as you go across a row and down a column.

That is the Angstrom. We use a Å to represent Angstroms (if you want to type that it’s
shift-alt-A on a Mac and control-shift-2, shift-A on a bogus, inferior, Windows or
Vista based machine).
Angstoms (Å)
http://upload.wikimedia.org/wikipedia/commons/1/11/Hydrogen_Atom.jpg
 Even the largest atoms are very
small. The diameter of a
uranium atom is only about
0.345 nanometers.
 0.345 nm = 3.45Å
 1nm = 10Å
 1Å = 1 x 10-10 meters
 A hydrogen atom is the smallest
atom. H has a diameter of only
0.74Å. About 13.5 billion
hydrogen atoms could fit onto
the edge of a meter stick.
What does an atom look like?
http://www.lanl.gov/orgs/pa/newsbulletin/images/Isotopes_logo.jpg
 In your notes, draw a
simple picture of an
atom. How about
Lithium.
 What did you draw?
AAA baseball club Albuquerque Isotopes logo
(you need to know what isotopes are!)
Atoms
http://upload.wikimedia.org/wikipedia/commons/thumb/e/e1/Stylised_Lithium_Atom.svg/270pxStylised_Lithium_Atom.svg.png
http://www.solarsystempictures.net/
Neutron
Proton
Electron
 Most people probably drew a
nucleus of some type with
electrons orbiting around it.
Lithium
Planets=Electrons
Sun=Nucleus
 Possibly it looks a little like a
mini solar system.
 Atoms are composed of
 Protons
 Neutrons
 Electrons
Subatomic Particles
Particle
Relative charge Relative mass Actual Mass of
(1 amu = mass of a Particle
proton)
Proton
Neutron
+1
1 amu
1.67 x 10-24g
0
1 amu
1.67 x 10-24g
-1
0 amu
9.11 x 10-28g
Electron
Electrons
 Electrons were the first particle discovered.
 JJ Thompson discovered the electron using cathode ray
tubes, and modified the model of the atom because of
this discovery.
 The electron has a very small mass. It is actually
1/1840th the size of a proton (0.00054 times). In other
words, if an electron was a smidge over a pound,
protons and neutrons would weigh almost a TON.
Electrons
http://educar.sc.usp.br/licenciatura/2003/mi/Millikan-Oil-Drop-Apparatus.gif
This is what he used to do it…
Robert Millikan
measured the
charge of the
electron in “The
Oil Drop
Experiments”
 Since it’s so small relative to a proton, we say that it has a relative mass
of 0.
 Electrons are negatively charged. Each electron has a charge of -1.
(Don’t forget the negative…it’s important!)
 If an atom loses an electron, what remains will have a positive charge. If
an atom gains an electron, it will have a negative charge.
Protons
http://web.buddyproject.org/web017/web017/images/atom.JPG
 Protons were the next subatomic
particle to be discovered.
 Protons were discovered by E.
Goldstein.
 Protons have a relative mass of 1
and a charge of +1.
Protons
http://www.periodictable.com/Items/020.6/index.html
Atomic Number
 Protons determine the “identity” of
an atom. The number of protons is a
property called “atomic number.”
Atomic numbers are on the periodic
table.
 The number of protons determines
what kind of atom it is.
 H has 1 proton
 C has 6 protons
 U has 92 protons
Protons
 Neutral atoms have the same number of protons
and electrons. (Makes sense, right?)
 The charges balance each other out. (Ca has 20
protons, and must have 20 negatively-charged
electrons to balance out those positive charges)
 Protons are located in the nucleus of the atom.
(Where are the electrons?)
Neutrons
http://www.ct.infn.it/~rivel/Archivio/chadwick.jpg
http://kwisp.files.wordpress.com/2009/05/adventures-jimmy-neutron-300-032707.jpg
 Neutrons are also located in the nucleus
of the atom.
Ooops, wrong
neutron!
Chadwick
 The nucleus was discovered by Ernest
Rutherford, a former student of JJ
Thompson.
 The neutron was the last particle
discovered, by James Chadwick, a
former student of Rutherford.
Neutrons
 More than likely, the fact that neutrons had no charge
made it harder to discover.
 The neutron has a relative mass of 1, the same as a
proton. However, it has no charge. Therefore, we say
that the charge = 0.
 The actual mass of a neutron is almost the same as that of
a proton. It is slightly different
 P = 0.0000000000000000000000016726 g
 N = 0.0000000000000000000000016749 g
Golf Balls In Beakers
My Little Model of the Atom
http://www.vias.org/physics/bk4_03_02.html
 These are in the lab somewhere. Find them.
 The pink balls represent protons.
 The white balls represent neutrons.
 Scientists quickly figured out by experimentation
how many protons each element had. If you want
to read more, check out the link above. Basically
though….
Golf Balls In Beakers

They were able to ionize (remove electrons—all of them) and found that

Hydrogen had 1 proton. They figured this out because they were able to
make H+ but not H2+

Helium had 2 protons. Again, they were able to make He+ and He2+ BUT
NOT He3+

Lithium had 3 protons.

Magnesium had 12 protons.

Bromine had 35 protons.

Uranium had 92 protons. For the heavier elements, they were not able to
remove all of the electrons. They had to do other experiments to figure
that out, using a ratio of a known atomic number and an unknown one.
Golf Balls In Beakers
 Not all the calculations were accurate at first, but
they figured them out in time.
 Scientists also knew what the masses of the
elements were, and the numbers weren’t adding up.
 Hydrogen was OK. It seemed to work out.
 But helium should weigh twice as much as
hydrogen. And lithium should weigh three times as
much. And carbon should weigh 6 times as much.
Golf Balls In Beakers
 But they didn’t.
 Helium was actually 4 times as heavy as
hydrogen. Lithium was 7 times as heavy.
Carbon was 12 times as heavy.
 And that was very confusing. However, the
neutron provided the final piece of the puzzle.
The neutrons accounted for the missing mass.
Neutrons
 It turns out that Helium has 2 protons AND
2 neutrons, which makes it 4 times as heavy
as hydrogen.
 Lithium has 3 protons and 4 neutrons, which
makes it 7 times as heavy as hydrogen.
 Carbon has 6 protons and 6 neutrons, which
makes it 12 times as heavy as hydrogen.
 The numbers added up.
The Nucleus
http://www.chemicalelements.com/bohr/b0019.gif
 Since the neutrons are located in the
nucleus, with the protons, substantially
ALL of the mass of the atom is contained
within the nucleus.
 Mass of nucleus in diagram
0.0000000000000000000000651 g
 Mass of electrons
0.0000000000000000000000000173 g
What element
is this??
 In other words, if the nucleus weighed 651
pounds, the electrons (combined) would
weigh less than a McD’s quarter-pounder
patty.
Strong Nuclear Force
 But positively charged things repel other positively
charged things, right?
 Why do all the protons stick together in the
nucleus?
 Why doesn’t it just spontaneously break apart?
Strong Nuclear Force
http://www.antonine-education.co.uk/Physics_AS/Module_1/Topic_5/strong_force.jpg
 The answer is strong nuclear force.
 It’s the strongest known force in the
universe. It far, far stronger than gravity.
 It only can be felt when the particles are
extremely close together, like when they
are packed together in the nucleus.
The secret’s in
the attractions
between the
quarks…
 Protons and neutrons are made of quarks.
It’s thought that the quarks attract other
quarks and hold the nucleus together, even
though all of the protons are positively
charged and would otherwise repel each
other.
Objective D
http://www.fiu.edu/~zhangj/cartoon_quantum3.gif
 Scientists, starting with
Dalton, came up with
models of the atom, to help
understand it and help to
predict its behavior.
 Check out the Chemical
History power point for
more details as the model
evolved over about 130
years from Dalton to
Quantum Mechanics.
Objective E
 We already know that the number of
protons is what makes an atom unique.
 Hydrogen has 1 proton.
 Carbon has 6 protons.
 Uranium has 92 protons.
So, if “ProtonMan”
 The “atomic number” is the number of
was a superhero,
protons. We sometimes use a Z to
he’d have a “Z” on
represent atomic number.
his suit??
Objective E
 So, for hydrogen, Z = 1
Don’t memorize
these…they are on the
Periodic Table
 For carbon, Z = 6
 For uranium, Z = 92.
 What is the atomic number for
 Aluminum
 Zinc
 Chlorine
Find THEM!!
Objective F
 So, Z (atomic number) tells us how many
protons an atom has. It does NOT tell
you how many ELECTRONS you have
(accurately) all the time!
 Most atoms have no charge. That means
that the number of protons (which are
positively charged) must balance out the
number of electrons (which are negatively
charged).
Objective F
 Unless you are TOLD that the atom has a charge, you
should assume it has no charge, and therefore, # of
protons = # of electrons.




Hydrogen (Z = 1) also has one electron.
Lithium (Z = 3) also has 3 electrons.
Carbon (Z = 6) also has 6 electrons.
Uranium (Z =92) also has 92 electrons.
 BUT REMEMBER The numbers of protons doesn’t
always equal the numbers of electrons.
Objective F
 Some atoms can lose electrons. When they do so,
they will form a positive “ion.” Some atoms can
gain electrons. When they do so, they will form a
negative “ion.”
 An ion is a atom which has an electrical charge
(either positive or negative). We’ll get to those in
Chapter 6. Na+1 and Cl-1 are formulas for ions.
 The number of protons cannot change. If the
number of protons changes, it’s no longer the same
element. Atoms can gain or lose electrons, but
they can NOT gain or lose protons in any chemical
reaction.
Schwartz’s Law
(a law I made up…hey, it’s my class)
 To calculate the number of electrons, use
 # of Electrons = Z – IC
 Where Z = atomic number and IC = ionic charge.
 Ex: Suppose we have a sodium ion with a + 1
charge. How many electrons does it have? Atomic
number (Z) is 11 (find this on Periodic Table) and
ionic charge is 1.
 # electrons = 11 - 1 = 10
Schwartz’s Law
 Let’s calculate a couple more…
 Ex: Suppose we have a sulfur ion with a - 2 charge.
How many electrons does it have? Atomic number (Z)
is 16 and ionic charge is -2.
 # electrons = 16 - (-2) = 16 + 2 = 18
 Ex: Suppose we have an zinc atom with no charge.
How many electrons does it have? Atomic number (Z)
is 30 and ionic charge is 0.
 # electrons = 30 - 0 = 30
6 neutrons
Objective F
http://www.atomicarchive.com/Physics/Images/isotopes.jpg
8 neutrons
 How do we calculate how many
neutrons we have?
 In order to do that, we need to
look at another property, called
atomic mass. The atomic mass of
an atom = THE SUM of protons
and neutrons.
 We will use another formula
Hey these are isotopes
again. Isotope = same #
of protons but a different
# of neutrons.
 # Neutrons = A – Z
 A = Mass Number
 So, what is Z again?
Objective F
http://www.lbl.gov/abc/Basic.html#Nuclearstructure
 Let’s look at an example. An atom of
Bromine (Br-80) has Z = 35 and Mass
Number = 80. How many neutrons does it
have? (Br-80 doesn’t mean bromine with a charge
of -80. When they write it like that, it’s a DASH
and 80 is the mass number)
 # Neutrons = Mass Number - Atomic
Number
 # Neutrons = 80 - 35 = 45
Special note
Isotopes of hydrogen:
1H
= hydrogen
1 proton, 0 neutron
2H
= deuterium
1 proton, 1 neutron
Objective F
 An atom of Deuterium has Z = 1, and Mass
Number = 2. How many neutrons does it
have?
 Since Z = 1, deuterium must be some type of
hydrogen. Hydrogen has Z = 1, and since
every element has a unique number of
protons, no two elements can have the same
number of protons.
 Deuterium is a form of hydrogen. When
deuterium reacts with oxygen it forms
something called “heavy water.” Heavy
1 proton, 2 neutrons
water is represented with the formula D2O.
Hydrogen is the only
 # of Neutrons = Mass Number - Z = 2 - 1 =
element with special
1
3H
= tritium
names for isotopes.
Power Point Assignment
 Pick an element…any element…
 Well, not just any element. Pick an element whose
symbol begins with the same letter as your first name.
 If for some strange reason none exists, say for instance
your name is Julie or Joe (sorry, no J elements) than use
the next letter.
 So Julie could pick Uranium
 And Joe could pick Osmium
 Research your element and write a 150 word summary
on what you learned.
Objective G
http://www.usagold.com/images/gold-coins-images.jpeg
http://finestimaginary.com/shop/images/medium/jewellery/au_MED.jpg
 How do isotopes differ from each
other? (You should know this by
now).
 Look at gold (Au) on the periodic
table. It says that the mass =
196.967. Since mass number and
atomic number are ALWAYS
whole numbers, how do we get
.967?
 The answer is that the atomic
masses on the periodic table are
averages.
Objective G
 They get that average atomic mass for Au by taking
into account ALL of gold’s isotopes.
 Isotopes differ from each other in the number of
neutrons. They behave the same CHEMICALLY
because all isotopes of the same element have the
same number of protons.
 The study guide talks about water and heavy water.
Heavy water is the same as water, except that
instead of H-1 it is formed using H-2, which is
sometimes called deuterium. So while water has a
molar mass of 18, deuterium oxide or heavy water
has a mass of 20 (2 + 2 + 16)
Objective G
http://www.damninteresting.net/content/heavy_water_ice.jpg
 Here’s an interesting fact…
 Ice cubes made out of “heavy water”
will not float. They sink to the bottom.
So it has different physical properties.
 Although it PROBABLY tastes the
same, you should NOT drink it
though. Too much of it can really mess
up your system.
Objective G
Don’t drink the HEAVY water!
 You can purchase D2O. For $33 (for 2 ounces), you can purchase
some from a company to be used as a “hydrating product” for
your skin. It’s enriched with deuterium (meaning it has more in it
than just normal water). It’s doubtful, in my opinion, that it does
anything special, but if you have a different hypothesis, and $33
to burn, there’s a link in your study guide.
 You can also purchase very pure heavy water as a scientific
reagent. We call that deuterium oxide, because a real chemist
would never order something that was called “heavy water.” It
sells for $330 for 250g (which is about 2/3 of a can of soda). This
stuff has been scientifically analyzed to contain 99.8% (at least) of
D2O, which is why it’s a lot more expensive than the “hydrating
product” for your skin.
Math Alert
Objective H
 How do we calculate the average
atomic mass?
 To do so, you need to know 2 things:
 All possible isotopes for an element
 The percent abundance for each (in
other words, how much of the whole is
represented by each isotope).
Objective H
 Let’s look at an example:
 Chlorine has 2 isotopes
 35Cl which is 75.77% of the total
amount of chlorine.
 37Cl which is 24.23% of the total
amount of chlorine.
 What is the average atomic mass of
Chlorine?
Objective H
 Cl-35 accounts for 75.77% of the total chlorine. CL-37
accounts for the rest.
 Remember to convert percents into decimals, you have to
move the decimal point 2 places to the left.
 You then mutiply the percentage (in decimal form) times the
mass number for that isotope. You do that for the other
isotope too, and then add the answers together.
 Avg Atomic Mass = 35 (0.7577) + 37 (0.2423).
 Avg Atomic Mass = 26.52 + 8.97 = 35.49
Objective H
 In our class, we are always going to round
average atomic masses to 1 decimal place.
 So, we’ll round 35.49 to 35.5 and that’s the
average atomic mass of Chlorine that we’ll
use.
 Why can’t you just average 35 and 37 (the
two isotopes) and get 36 as the average
atomic mass? Why is that wrong?
The Periodic Table
 We’ve described the Periodic Table as
 The biggest cheat sheet in science
 The best tool we have in Chemistry
 Your best friend on the test
 Suppose we didn’t have a Periodic Table.
You would have to memorize every fact
about every element.
This is a map…
What does it tell you?
 It shows you the states. If you know approximately
where Virginia is, you can easily find it on the map.
 It shows you state abbreviations. If you don’t know
where Virginia is, or even what it sort of looks like, you
can find it by using the abbreviation “VA.”
 It shows you data for each state…




The name of the state capital.
The approximate location of the state capital
What other states are above, below or next to each state.
The sizes of the states..which are large and which are
smaller.
What else does it tell you?
http://www.destination360.com/maps/virginia-map.gif
 Well, that’s about all, really.
 But you can make some assumptions about
the states based on their position on the
map.
 For example, VA borders NC, MD, TN, WV
and KY. You might assume that VA has
some things in common with each of these
states.
 You would be right.
Anything else?
http://wwp.greenwichmeantime.com/images/usa/montana.jpg
 You might also assume that Virginia
doesn’t have much in common with
WY, MT, ID or OR. All of these are
large western states. How is Virginia
different from these?
 It’s smaller in terms of area. Montana
is the 4th largest @ 147,000 mi2 and
Virginia is 35th largest @ less than
43,000 mi2
 It’s much larger in terms of
population. Virginia is 12th largest
with just over 7 million people.
Montana is 44th largest with just over
900,000 people. To put that into
perspective, four cities in Virginia
(Virginia Beach, Norfolk, Arlington
and Fredericksburg) have as many
people as Montana.
What does this have to do
with Chemistry?
 Not a lot.
 Except that the Periodic Table of the Elements is a lot
like a map to guide you through Chemistry.
 Like the US map, it divides the territory not into states,
but elements. Elements that border other elements have
more in common with each other than elements that are
on opposite sides of the table.
 If you can’t read a map, you might get lost on a trip.
And if you can’t understand the Periodic Table, you
might get lost on your trip through Chemistry.
Objective I
 Suppose we didn’t have a Periodic Table. You would
have to memorize every fact about every element.
 You would have to memorize every symbol.
 You would have to memorize atomic numbers.
 You would have to memorize atomic mass.
 You would have to memorize which elements behaved
similarly to other elements.
 And, a whole lot more.
Objective I
http://chemheritage.org/pubs/ch-v25n1-articles/images/mendeleev.jpg
 That’s what scientists did for many years.
 However, a Russian chemist named
Dmitri Mendeleev changed all that for us.
 He had the bright idea to try and organize
all the known elements (back then, about
70 of them were known) into some kind
of logical order.
Dmitri
Mendeleev
 Mendeleev didn’t know about atomic
number. Protons hadn’t been discovered
yet. However, he did know atomic mass.
Soooo, he organized his table by atomic
mass.
Objective I
Nothing “fit”
into the holes, so
he left them
blank, and he
essentially
challenged the
rest of the world
to find them.
 Just putting them into some kind of logical
order isn’t that much of an accomplishment.
Many people could have done that. (In fact,
others did, but prior to Mendeleev, no one got
it exactly right.)
 But Mendeleev left “holes” in the table to
represent undiscovered elements. For
example, the element under aluminum hadn’t
been discovered yet. He called that ekaAluminum. Eka was a prefix which meant
below.
 He also called the element under silicon ekaSilicon.
Objective I
 But many people could have left holes for “still
undiscovered” elements. I’m still not that impressed.
(Although to be honest, scientists at the time snickered at
Mendeleev’s “boldness” in suggesting that his table would be
correct, if only people would discover some new elements to
put in the holes.)
 But he went even further. Using his new table, he “predicted”
that when those elements were discovered, they would have
certain types of properties.
 He predicted the boiling point, melting point, density, color,
etc. And you know what: when eka-Aluminum was finally
discovered, he was right!
 OK, now that impresses me. That takes guts. Not only did he
suggest that new elements would be discovered, but he even
predicted how they would look and behave.
Objective I
http://upload.wikimedia.org/wikipedia/commons/d/dd/Henry_Moseley.jpg
 Eka-Aluminum is actually Gallium (Ga). EkaSilicon is Germanium (Ge).
 That’s what Mendeleev did. And after the
“holes” started to get filled in, just as
Mendeleev had predicted, there was no more
snickering.
 But remember, the table was organized by
atomic MASS, not atomic number.
 After the discovery of the proton, another
chemist, Henry Moseley, revised Mendeleev’s
table slightly so that it was listed in atomic
number order. That’s the table we have
today.
Objective J
http://www.dayah.com/periodic/Images/periodic%20table.png
G
ro
u
p
s
Periods
 A LITTLE PERIODIC GEOGRAPHY…
 Rows on the Periodic Table are called PERIODS.
 Columns on the Periodic Table are called GROUPS or FAMILIES
Objective J
 Group IA (1) = Alkali Metals
 Group IIA (2) = Alkaline Earth Metals
 Group VIIA (17) = Halogens
 Group VIIIA (18 or 0) = Noble Gases
 Group IB (Cu, Ag, Au) is sometimes called the
Royal Family.
Objective J
 Groups IA - VIIIA form the REPRESENTATIVE
ELEMENTS (orange on my board)
 Groups IB - VIIIB form the TRANSITION METALS
(black on my board)
 The two rows underneath the table are called the
Lanthanides (top) and the Actinides (bottom; it was
Glenn Seaborg who came up with the concept that
the actinides behaved like the lanthanides).
Objective J
 The table can be divided into 4 blocks.
 The “s block” is Group IA, IIA and He. (2 orange rows on
left + Helium)
 The “p block” is Groups IIIA - VIIIA (6 orange rows on
right, not including Helium)
 The “d block” is the transition metals (the black section)
 The “f block” is the Lanthanides and Actinides.
 The jagged line separates the metals from the nonmetals.
Metals are to the left and are MOST of the table. Nonmetals
are to the right. It’s important to know what’s a metal and
what’s not.
Objective J
 Some of the elements along the jagged line
are a special case called metalloids.
 B, Si, Ge, As, Sb, Te and Po are metalloids.
Metalloids behave like metals in some ways,
but also like nonmetals in some ways.
Na
 Find Na on the table.
 Na stands for sodium. Sodium is one of those elements
that we’re going to use over and over this year. Might as
well memorize it now.
 Of course that makes no sense, unless you know that the
Latin name for sodium is natrium, and then it makes a
lot more.
 Why did we give it a Latin name? Well, this British guy
named Sir Humphry Davis gave it that name back in
1807 when he discovered it.
K
 Right underneath sodium is K or potassium. Ok,
does that have a Latin name too? Yes, Sir Davis
discovered this too and he named it kalium.
 Why? I don’t know but the guy that discovered it
got to name it and that’s what he decided to name
it.
 Based on your understanding of maps do you think
K has a little or a lot in common with Na?
Alkali Metals
 Sodium and potassium and all the rest of the
elements in that group are alkali metals.
 The alkali metals all have one valence electron. That
similarity is what makes them behave the same
chemically.
 They are very reactive. Reactivity is highest on the
outer edges of the table and elements get less
reactive the closer they are to the center of the table.
Lithium is the least reactive alkali metal and
reactivity increases as you go down the group.
Noble Gases
 The noble gases are very stable. They are unreactive
because they are so stable.
 The noble gases all have 8 valence electrons.
Helium is an exception in that it only has 2.
 The noble gases are obviously gases at normal room
temperature.
Alkaline Earth Metals
& Halogens
 Group IIA or Group 2 are called “the alkaline earth
metals.” They have 2 valence electrons.
 Group VIIA or Group 17 are called “the halogens.”
The halogens all have 7 valence electrons, and like
the alkali metals, they are very reactive (fluorine is
most reactive and reactivity decreases as you go
down the group).
Customize your table
 Highlight the s block in BLUE
 Highlight the p block in ORANGE
 Highlight the d block in YELLOW
 Highlight the f block in PINK
 Circle the element symbols for the gases.
 Draw a square around the symbol for Hg and Br. These are the
only 2 liquids at room temperature.
 Put a * in the box for H, O, N, Cl, Br, I, and F. These are diatomic
elements.
 As you learn more, continue to customize your periodic table.
Power Point Assignment
http://sciencespot.net/Media/ptablebasics.pdf
 Get the Periodic Table Basics Assignment from me. (I
found this assignment at sciencespot.net, and special
thanks to Tracy Trimpe for not having to reinvent this
wheel.)
 Do the assignment. You will turn in the questions on the
back PLUS a simplified version of the Periodic Table that
you will make in the assignment.
 To do this assignment, you need to know what a Bohr
Diagram is and what a Lewis structure is.
 Continue on to find out.
Power Point Assignment
 A Bohr diagram shows the electrons in “energy
levels.”
 The energy levels are represented by circles. The
inner most circle can have 2 electrons. The other
outer circles, can have a total of 8 each.
 You represent the electrons with a dot, starting on
the inner circle, filling that up, and then moving
outward. You must fill the circle completely before
you can move to the next circle.
 The assignment gives you an example using Boron.
Power Point Assignment
 Once you have the Bohr diagram done, the Lewis
structure is very easy.
 You represent only VALENCE electrons on the Lewis
structure.
 Valence electrons are electrons which are in the highest
occupied energy level. In other words, the electrons in
the outermost circle in your Bohr diagram are valence
electrons.
 They give you an example using Boron. B has 3 electrons
in the outer circle, so the Lewis structure has 3 dots.
Power Point Assignment
http://www.ausetute.com.au/lewisstr.html
 A Lewis structure can have a maximum of 8 dots.
 You put one dot on each side of the symbol (top,
bottom, left and right), until each side has a dot.
 Then you can start pairing them up, until every
side has 2 dots.
Oxygen
Lewis
structure
 When every side has two dots, you can’t put any
more dots on the structure. If you need to, you did
something wrong.
The End
Next you should look at the Chemical History power point.
Then…
Advanced Chemistry should go to Chapter 28
powerpoint.
Chemistry should go to the Special Topics for SOL 2
powerpoint.