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Title: Chem Review 3
PART 1 TOPIC: HISTORY OF PERIODIC TABLE
EQ: How was the first PT organized and how has it changed over the years?
Date
Title and
Highlight
Topic:
EQ:
NOTES: • Write out the notes from my website.
Use different types of note-taking methods to
help you recall info (different color
pens/highlighters, bullets, etc)
• When I lecture we will add more info, so
leave spaces in your notes
• DRAW ANY PICTURES, FIGURES, AND
WRITE OUT ANY PRACTICE
PROBLEMS/QUESTIONS.
• WE WILL ANSWER THEM TOGETHER.
So…LEAVE SPACES SO WE CAN
ANSWER QUES.
Summary (end of notes) :
1-2 Sentences of what you learned
Reflect
Question:
Reflect on
the
material by
asking a
question
(its not
suppose to
be
answered
from
notes)
The periodic table is the most important tool in the chemist’s toolbox!
Why is the Periodic Table important to me?
• You get to use it on every test.
• It organizes lots of information about all the known elements.
Dmitri Mendeleev: Father of the Periodic Table In 1869 he published a table of the elements.
1834 - 1907
A first look at the periodic table Dmitri Mendeleev organized all of the elements that were known at the time into rows and columns based on their chem/phy similarities and their masses.
Periodic Table •The table is called “periodic” because the pattern of similar properties repeats as you move from period to period.
Dmitri Mendeleev HOW HIS WORKED…
70 known elements.
Organized rows (periods) by increasing atomic weight.
Put elements in columns (groups) by their properties.
SOME PROBLEMS…
He left blank spaces for undiscovered elements. (Turned out he was right!)
He broke the pattern of increasing atomic weight.
Used his P.T. to predict the physical properties of three elements that were yet unknown.
Problems arose when new elements were discovered. Looking at our modern P.T., can you identify what problems might have caused chemists a headache?
Ar and K
Co and Ni
Te and I
Th and Pa
The fact that Mendeleev’s predictions for Sc, Ga, and Ge were amazingly close to the actual values, his table was generally accepted.
Henry Moseley
1887 - 1915
In 1913, through his work with X-rays, he determined the atomic number of the elements*……elements should be arranged in order of increasing atomic number is known as the periodic law.
Glenn T. Seaborg
After co-discovering 10 new elements, in 1944 he moved 28 elements out of the main body of the periodic table to their current location below the main part of the P.T. :Lanthanide and Actinide series.
1912 - 1999
Current Periodic Table:
How the P.T. has changed over time?
Current P.T.
Increasing ATOMIC NUMBER!!
Elements in the same group have similar chemical and physical properties!! (Mendeleev did
that on purpose.)
Past P.T.
• Increasing Mass number
(not any more!!!)
• Elements in the same group have similar chemical and physical properties!!
Still the same!!!
Title: Chem Review 3
PART 2 TOPIC: ORGANIZATION OF PT
EQ: How is the PT organized and why is it useful for us studying chemistry?
Students…. The next 6 slides are notes about the Periodic Table and how it is organized.
You can either make a sketch (please don’t draw every box) for each slide
OR
Make one BIG (entire page) Sketch and label all notes on that one sketch.
Your choice!
The horizontal rows of the periodic table are called PERIODS (7).
Make a Sketch
with notes
The vertical columns are called GROUPS (18), or FAMILIES.
The elements in any group have similar physical and chemical properties!
Make a Sketch
with notes
1A
2A 3A 4A 5A 6A 7A
8A
Elements in the 1A-8A groups are called the representative or main group elements
Make a Sketch
with notes
The group B are called the transition elements
Make a Sketch
this with notes
The elements in the periodic table can be broadly classified as metals,
nonmetals, and metalloids.
Types of Elements
Sketch this
with notes
3 classes of elements - METALS
Located to the _______ of the dark zig-zag line
All Solids!!! Except one – who is it??
shiny surface
Tend to be white/gray/silvery (common exceptions: copper and gold)
◦ ______________ (you can pound it into a flat sheet)
◦ ______________ (you can draw it into a thin wire)
◦good _______________ (heat/electricity)
◦Metals tend to LOSE electrons in chemical changes.
left
malleable
ductile
conductors
3 classes of elements - NONMETALS
Located to the ___________ of the dark zig-zag line.
◦_______ surface
◦ ______________
◦Some are solids and some are gases. Only 1 liquid.
◦good _______________ and poor conductors
◦Nonmetals tend to GAIN electrons in chemical changes.
◦Vary in color (P - red/white, S – yellow, C – black/clear, I – purple, Br – brownish red, etc)
right
dull
brittle
insulators
sulfur
Sketch this
with notes
3 classes of elements – METALLOIDS (only 8)
Located on the border of the dark zig-zag line.
◦ the dividing line between metals and nonmetals.
◦ All SOLIDS!
◦ Also called “semimetals”
◦ Behave (chemically) as nonmetals, but look physically & electrical conductivity resembles metals.
◦ Semiconductors – they do conduct some heat/electricity
◦ Used in computers, cell phones, and other modern gadgets.
silicon
Sketch this
with notes
Hydrogen
Hydrogen belongs to a family of its own.
Hydrogen is a nonmetal!!!
It’s a diatomic, reactive gas.
Facts
Hydrogen was involved in the explosion of the Hindenberg.
Hydrogen is promising as an alternative fuel source for automobiles
Group 1 - Alkali Metals (not H!!!)
•Very reactive metals (solids) with air
and water
•Never found pure in nature, too reactive
(always combined with something else in
nature like in salt).
•All have one valence e-
•Soft enough to cut with a butter knife
•Reactivity of these elements increases
down the group
Alkali Metal Family
Video Clip
Sketch this
with notes
Group 2 - Alkaline Earth Metals
•Reactive metals (solids) that are always
combined with nonmetals in nature.
•Not found pure in nature (too reactive but
less reactive than alkali metals)
• “Alkaline” means “basic”
•All have 2 valence e-
•Mg and Ca important for our body!!!
•Also, used in batteries
Sketch this
with notes
Groups 3-12: Transition Metals Sketch this
with notes
All solids except Mercury
Less reactive harder metals
Includes metals used in jewelry and construction.
Metals used “as metal.”
Transition Metals Groups 3-12
Group 14 - Carbon Family
4 Valence e-
Elements important to life and computers (Si and Ge).
Carbon is the basis for an entire branch of chemistry called ORGANIC Chem.
Sketch this
with notes
Group 15 - Nitrogen Family
5 valence e-
Nitrogen makes up over 80% of the atmosphere.
Nitrogen and phosphorus are both important in living things.
The red stuff on the tip of matches is phosphorus.
Sketch this
with notes
Group 16 - Oxygen Family or Chalcogens
6 valence e-
Oxygen is necessary for respiration.
Many things that stink, contain sulfur (rotten eggs, garlic, skunks,etc.)
Sketch this
with notes
Group 17 - Halogens
• 7 valence e-
• Very reactive, diatomic,
nonmetals
• Not found pure in nature
• Always combined with other
elements in nature .
• Used in some light fixtures
• Used as disinfectants and to
strengthen teeth.
Sketch this
with notes
Group 18 - Noble Gases • 8 valence e- (except He has 2 e-)
• VERY unreactive, monatomic gases
• Only elements found pure in nature
• Colorless, odorless, and unreactive;
• Don’t form compounds!!!
(These are also called “Inert gases”)
• Used in lighted “neon” signs and
balloons.
Sketch this
with notes
A
l
k
a
l
i
M
e
t
a
l
s
A
l
k
a
l
I
n
e
E
a
r
t
h
M
e
t
a
l
s
N
o
b
e
l
G
a
s
e
s
H
a
l
o
g
e
n
s
Transition Metals
Inner Transition Metals
Representative Elements
Transition Elements
Rep
resen
tativ
e E
lem
en
ts
METALS
Periods
Gro
up
s
Nonmetals
QUESTIONS
Title: Chem Review 3
PART 3 TOPIC: ISOTOPES
EQ: What part of the atom changes when you have isotopes of elements?
Atomic number (Z).
Protons determines the identity of the element.
A# = p+ = e- (atoms are
neutral)
The Mass Number (A),
(rounded to the nearest
integer)
Mass# = p+ + no
# of neutrons = mass # – p+
Isotopes: When the Number of Neutrons & Mass # Varies
All atoms of an element have the same # of protons.
Atoms with the same # of protons but different # of neutrons (this causes the mass # to also change) are called isotopes.
EXAMPLE OF AN ISOTOPE
Cl 35
17 Cl 37
17
20 NEUTRONS
ATOMIC MASS
18 NEUTRONS
ATOMIC NUMBER
So…
Atomic# = p+ = e-
(if atom is neutral) HOWEVER…..what if the atom is not neutral?
Electrons
•Electrons can be lost or gained = Chemical
Reaction, which make up more than 99% of
all rxns in life)
• When electrons are lost or gained, IONS are
formed.
•And electrons won’t equal protons no
more!!! Atomic# = p+ = e- •
Ions: Cations vs. Anions
Positive ions (lose e-) are called cations.
Negative ions (gain e-) are called anions.
The charge of an ion is shown in the upper right corner of the symbol.
Ion Symbol Notation
X Mass
number
Atomic
number Subscript →
Superscript → +2
Lost 2 e-
So… how do you know how many electrons atoms will lose or gain to form an ion?
Ions and the Periodic Table
The # associated with the A groups above each representative (main-group) column on the P.T. —1 through 8—gives the number of valence electrons (electrons on the far outside of the atom – these e- are the ones used first for chemical bonding!!!)
The key to predicting the charge acquired by an element is its position in the periodic table relative to the noble gases. Why noble gases?
Elements that form predictable ions
If an atom has a charge associate with it, it is an ION:
88 2
38 Sr
How many protons, neutrons, and electrons are there?
Important: If an atom has a negative charge = an anion. If an atom has a positive charge = a cation.
Practice Problem #1
Determine the number of protons, neutrons and electrons in this atom. Is this a cation or anion?
356
26 Fe
Practice Problem #2
Determine the number of protons, neutrons and electrons in this atom. Is this a cation or anion?
232
16
S
Practice Problem #3 How many protons, neutrons & electrons are there in the following?
a. Cl-38 d. 35Cl-1
b. Br-80 e. 32S-2
c. N-14 f. 56Fe+3