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CHAPTER 3
MATTER AND ATOMIC
STRUCTURE
Questions of the Day – 1/9/14
• 1. Which of the following is defined as something that
cannot be broken down into simpler substances?
• A. Mixture
• C. Compound
B. Element
D. Panda
• 2. What of the following is the smallest part of a
substance which still has the characteristics of that
substance?
• A. Proton
• C. Atom
B. Element
D. Quark
• 3. How many protons does Helium have?
• A. 1
B. 2
• C. 3
D. 4
Today’s Objectives
• Define and describe element, atom, and the periodic table
• Identify and describe the sub-atomic particles within
atoms
• Use the atomic number and mass number of elements to
create diagrams of their atoms
What Makes Up All Matter?
Element
• Something that can’t be
broken down into simpler
pieces.
• Exp: Gold
Atom
• The smallest part of the
element that still has all of
the same characteristics
of the element.
• Can be melted, divided into
small pieces, hammered
flat….still gold
• 92 Naturally Occurring
• 20 Man-made
• Atoms are made up of
• 1). Protons
• 2). Neutrons
• 3). Electrons
Parts of an Atom
Proton
• Small particle found inside the
nucleus of an atom with a
positive charge
• Usually represented by a plus sign
when atoms are drawn out.
• Atomic Number = Tells you the
number of protons an element
has.
• Located above the element
abbreviation on the periodic table of
elements.
• Periodic Table is organized by
atomic number.
• You cannot change the number of
protons found within an atom without
changing the element you are working
with.
Parts of an Atom
Neutrons
• Small particle found inside
the nucleus of an atom with
a neutral charge/ no charge
• Hold together all the positive
charges in the nucleus.
• Act as the glue to prevent all
the positive charges from
repelling each other.
• Stabilizes the nucleus
• Have to use a little subtraction
to find the number of
neutrons.
Mass Number
• The rounded whole number
located beneath the
abbreviation of the element.
• Round the decimal point to the
nearest whole number to obtain
the mass number (the exact
numbers of protons and neutrons
in the nucleus of an particular
atom).
• Use the Mass Number of an
element to find the number of
neutrons by subtracting the
number of protons (Atomic
Number) from it.
Parts of an Atom
Electrons
• Smallest particle with a
negative charge found
organized into clouds
outside the nucleus of an
atom.
• For all ‘normal’ atoms you
can find the number of
electrons because
positive and negative
charges must cancel
out….
• So, an atom must have
the same number of
protons and electrons.
• Atomic Number also tells you
the number of electrons.
Parts of an Atom
Electron Arrangement
• These negative particles
• Electrons are negatively
are held in by their
attraction to the positively
charged nucleus.
charged and want to repel
each other.
• Remember opposites attract
they are as far away from
another electron as possible.
• But, usually you can’t fit
all of the electrons right
around the nucleus.
• Why?
• They sort themselves so
Question of the Day – 1/10/14
• 1. How many protons does the element Silver have?
• Answer: 47
• 2. How many neutrons does the element Phosphorous have?
• Answer: 16
Today’s Objectives
• Practice using the Periodic Table to determine an atom’s
proton, electron, and neutron counts.
• Use the atomic number and atomic mass number of
elements to create diagrams of their atoms
Parts of an Atom
Electron Arrangement
• The best arrangement for
electrons ends up with them
dividing among energy levels
and because electrons repel
each other you can only have a
certain number of electrons in
any energy level.
• Because electrons repel each
other you can only have a
certain number of electrons in
any energy level.
Energy Level Electron Assignment
Energy Level
Max number of
electrons
1st Shell (closest
to the nucleus)
2
2nd Shell
8
3rd Shell
8
Parts of an Atom
Valence Electrons
• The electrons that are in
the energy level farthest
away from the nucleus.
• These electrons give us a
lot of information about
the element.
• How/If it is reactive.
• Chemical Properties
Question of the Day – 1/13/14
• 1. How many valence electrons does Magnesium have?
• Answer: 2
• 2. How many valence electrons does Beryllium have?
• Answer: 2
• 3. Without drawing or calculating it out, (look at the trend in
your periodic table from questions 1 and 2), take an educated
guess on how many valence electrons
Strontium has.
Answer: 2
The trend is the vertical grouping of these elements. All
elements in a vertical group have the same number of valence
electrons.
You do not need your clicker today!
• Find a blank sheet of paper (Not notebook! No lines!)
• From yourself
• From the black files under the bookshelf
• Study/prepare for quiz
• Any questions?
Quiz - On your blank piece of paper:
• For the element: Aluminum
• Identify the total number of Protons -> P = _____
• Identify the total number of Neutrons -> N = _____
• Identify the total number of Electrons -> E = _____
• Draw the Bohr Diagram
• You do not need to draw the protons or neutrons inside the nucleus
• You may simply leave the inside of the nucleus blank
• Draw the Lewis Diagram – also known as the Electron Dot Diagram
• After your are done, put your paper in the wire basket. Be sure
your name is on it! Grab 2 new papers. Please remain quiet
while others finish their quizzes. You may read (check out my
book/magazine selection) or do some other quiet activity.
Periodic Table Vocabulary
•
•
• Periods = Rows that travel across the periodic table
horizontally
•
• Groups = Columns of elements that are grouped vertically
on the periodic table.
Periodic Table Trends
• For Atoms, 8 is the magic number of valence electrons
they want (or in hydrogen and helium’s case ~ 2).
Group 1: Alkali Metals
• All of these elements
have 1 electron in their
outer shells.
• Like to get rid of their
electron.
• Highly reactive
• Metals
• Low Density
Group 2: Alkaline Earth Metals
• All of the elements have
2 electrons in their
valence shell.
• Like to get rid of their
electrons.
• Reactive
• Silver Colored
• Soft Metals
Groups 3-12 Transition
Elements
• Have a vast array of
properties
• Characteristics vary
greatly
Group 13 and 14
• 13 is the Boron family
• 14 is the Carbon family
• Has 3 electrons in its
• Has 4 electrons in their
valence shell.
• Most of these elements
like to share electrons
instead of getting rid of
them.
valence shell.
• Really like to share their
electrons.
Group 15: The Pnictogens
• Have 5 electrons in their
valence shell
• Like to share instead of
getting rid of their
electrons.
• Very Stable
Group 16 and 17
• 16 = Chalcogens
• Have 6 valence shell
electrons
• Most elements in this
family like to steal
electrons.
• 17 = Halogens
• Have 7 electrons in their
valence shell.
• Elements in this family
really like to steal
electrons.
• Elements in all states of
matter
Group 18: The Noble Gases
• Why are these so
• Odorless
special/unique?
• Content with the number
of electrons they have.
• Colorless
• Full valence shell of 8.
• Low Reactivity
• Very Few Compounds
Exist
Electron Arrangement Examples
Hydrogen = atomic number 1
1p
Helium = atomic number 2
Lithium = atomic number 3
3p
Beryillium = atomic number 4
2p
4p
Electron Arrangement Examples
Carbon = Atomic number 6
Neon = Atomic number 10
6p
Oxygen = Atomic number 8
8p
10 p
Sodium = Atomic number 11
11 p
Ionic Bonds
Electron Exchange
• Some atoms bond by
gaining or losing
electrons.
Opposites Attract
• If an atom gains electrons
then it will be negative
• Anions
• If an atom loses electrons
• Ion = an atom with more
then it will be positive.
• Cations - cats are positive people
or less electrons.
• Once atoms become
charged they attract
• Positive and Negative
charges attract.
Question of the Day – 1/15/14
• 1. In order to get to the magic number 8, what does
Calcium “want” to do?
• A. Give 2 - correct answer
• C. Steal 2
B. Give 1
D. Steal 1
• 2. A cation is a…
• A. Negatively charged ion
B. Negatively charged isotope
• C. Positively charged ion–correct D. Positively charged isotope
• 3. What is the official name of Group 18?
• A. Pnictogens
B. Noble Gases–correct
• C. Boron Group
D. Alkaline Earth Metals
Ionic Poker
• For each round, say a person’s name aloud.
• Decide what the element on the card “wants” to do
• “Give 2” or “Steal 2” etc
• Say it aloud. Do that action with the person whose name
you called at the beginning of the round.
• If you are incorrect, you must give everyone in the group
the correct amount (even if it is supposed to be steal)
• Be the highest chip holder at the end of the class period.
Ionic Poker Rules Change
• For each round, say a person’s name aloud.
• Decide what the element on the card becomes
• Becomes “Positive 2” or “Negative 2”
• Say it aloud. Do that action with the person whose name
you called at the beginning of the round.
• If you are incorrect, you must give everyone in the group
the correct amount (even if it is supposed to be steal).
• If the other person does the wrong action, he/she has to
give everyone in the group the correct amount.
• Be the highest chip holder at the end of the class period.
Question of the Day – 1/16/17
• 1. What is the correct symbol for the Magnesium ion?
• A. Mg2+
B. Mg+2
• C. Mg2D. Mg1+
• 2. What does the element Aluminum “want” to do?
• A. Give 3
B. Steal 3
• C. Give 5
C. Steal 5
• 3. What is the official name of Group 2?
• A. Alkali Metals
B. Alkaline Earth Metals
• C. Noble Gases
D. Chalcogens
Question of the Day – 1/17/14
• 1. What would the symbol for the Bromine ion look like?
• A. Br2+
B. Br1• C. Br1+
D. Br2• 2. What is the official name for Group 17?
• A. Halogens
B. Boron Group
• C. Chalcogens
D. Pcnitogens
Making Compounds
Compounds
• A compound is a
substance made of atoms
from 2 or more different
elements.
• Chemical Bond = the
forces that hold elements
together in compounds.
• Makes sure that the valence
shells of elements are filled.
• Most compounds are very
different from the
elements that make them
up.
• Exp Water and Salt
• Occurs through giving and
receiving electrons or by
sharing electrons
Ionic Bonds
• Once atoms become ions
positive and negative
charges attract.
• Each atom is charged;
either positive or negative.
• But, the compound is
• The attraction between
two atoms with opposite
charges is called an Ionic
Bond.
• Strongest type of bond.
neutral.
• Positive and negative
charges cancel out.
• http://www.youtube.com/w
atch?v=xTx_DWboEVs
Ionic Bond Practice
• We have a transfer of
electrons between atoms
going on
• Sodium Chloride
• Table Salt
• NaCl
More Practice
Ionic Bond
• Build LiF
• Make Lithium (Li) and
Fluorine (F) join in an ionic
bond.
Ionic Bon
• Build Magnesium
Chloride
• Make Magnesium
(Mg) and Chlorine (Cl)
join in an ionic bond
• Mg2+
• Cl1• MgCl2
Question of the Day
• 1. What is the charge on a Calcium (Ca) ion?
• A. 2+
B. 2• C. 1+
D. 1• 2. What does Sodium (Na) “want” to do?
• A. Steal one
B. Give one
• C. Steal two
C. Give two
• 3. How many electron shells (energy levels) does
Phosphorous (P) have?
• A. 1
• C. 3
B. 2
D. 4
Covalent Bonds
• In a covalent bond, atoms fill up their valence shells by
sharing electrons.
• When two atoms are held together by a shared pair of
electrons we call this process a covalent bond.
•
• Molecule = 2 or more elements held together by a
covalent bond.
2.8 Covalent bonds
Bond Strength
• Ionic > Covalent!!
Question of the day
• 1. What word should you pair with “covalent?”
• A. Sharing
B. Stealing
• C. Giving
D. Penguins
• 2. If you were going to bond Calcium (Ca) and Fluorine
(F), how many of each would you need?
• A. 2 Ca; 1 F
• C. 1 Ca; 1 F
B. 2 Ca; 2 F
D. 1 Ca; 2 F
Different Types of Atoms
Isotopes
• What is an isotope?
• When an element has more or
less neutrons then it is
supposed to.
• Gains or loses neutrons due to
high energy particle
interactions
What Stays the Same?
• The number of protons does
not change.
• The element identity would
change.
• The number of electrons
does not change.
• Has the same properties
• No charge is present
• Atom weighs less or more
Mass Number – individual atom’s mass
• This is what you used to find neutron count before
• What is an individual atom’s mass number?
• Protons Mass + Neutrons Mass + Electrons Mass
• But electrons don’t matter!
• 1,000,000,000 + 1,000,000,000 + 0.000000000000001 = 2,000,000,000
Isotopes
Mass Number
This averaging is why we see decimals on the
periodic table for the element’s mass number.
• Existence
• We know that isotopes exist
because we have observed them
in nature.
• Scientists averaged out all of the
mass numbers they discovered of
an element and came up with
atomic mass.
• Atomic Mass = The average
mass number for an element.
• Abundance matters!!!!
• http://www.youtube.com/w
atch?v=Jdtt3LsodAQ
Isotope Practice
• Lithium: Make a normal atom of Lithium (Li)(Lithium-7)
• Transform this normal atom into the isotope of Lithium-6
• Fluorine: Make a normal atom of Fluorine ( F) (Fluorine-
19)
• Transform this normal atom into Fluorine-17
• Phosphorus: Make a normal atom of Phosphorus (P)
(Phosphorus-31)
• Transform this normal atom into Phosphorus-27
Protons =M side up
Neutrons = Blank side
Electrons = Pennies
Isotopes
Existence
• How do isotopes form?
• Some Isotopes already exist
• Others are formed by
collision of particles.
• In upper layers of the
atmosphere.
• Matter is exposed to intense
light; UV rays, gamma rays,
and x-rays.
• These intense rays can break
matter up and force particles
in or knock particles out.
• General Rule: The larger the
element’s nucleus the harder
it is for it to hold on to an
extra neutron.
Radioactivity
• All isotopes eventual want to
Unstable Isotopes
return to their “normal state”
• Some Isotopes take a very long
time to get back to their normal
number of neutrons.
• We call these isotopes stable.
• They can stay as isotopes for a
long time
• Exp: Carbon Isotopes 13, Oxygen
17
• Other isotopes return to their
normal number of neutrons
very quickly
• These Isotopes are unstable
• These want to get back to their
normal amount of neutrons badly.
• Exp: Radium, Palonium
• Begin to throw away particles
• This can release lots of energy.
• If Isotopes get rid of their
neutrons slowly, then the
emit energy (radiation)
slowly over time.
• If Isotopes throw away
their neutrons quickly,
then they emit huge
amounts of energy
quickly.
• We call this radioactivity
Nuclear Bombs
• Uranium 235 + 1 neutron => Uranium 236
• Very unstable
• Decays really quickly but goes overboard (gives off too many
neutrons) releasing a ton of energy in the process
• Creates a chain reaction of neutrons hitting other uranium 235
atoms which creates more neutrons which hit other uranium 235
atoms, etc.
Radioactive Isotopes
Half-Life
• The amount of time it take
for half of the sample (half
of the atoms) to decay.
• Long Half-Life = Long time
for half of atoms of a sample
to decay = Stable
• Short Half Life = Short time
for half of atoms of a sample
to decay = Unstable
Half-life