1 Today is Friday, January 11 th DO NOW Be sure to take a copy of Chem w/s and complete #1 - 9.
Chem Do Now
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Transcript of Chem Do Now
Chem Do Now• Hand me all assignments you are submitting• Gather all your materials• Find your name on the seating chart on the
board up front and move your seat.• By the time the timer is up, you should be
seated with your notes pages out.• Anyone not in their assigned seat at the time
of the buzzer must go get a late pass.• Talk to me AFTER CLASS if you have an issue,
I WILL NOT move you today during class.
Ions
Nuclear Charge• In the nucleus there are protons and
neutrons– Protons are positive– Neutrons are neutral
• If the nucleus has 3 protons it has a charge of 3+
Neutral AtomIn a neutral atom, there are
equal numbers of protons and electrons
Each positive is cancelled
by a negative.
Ions• In an ion, there are unequal numbers
of protons and electrons
3 + charge4 – charge1 – charge
Ions• In an ion, there are unequal numbers
of protons and electrons
3 + charge2 – charge1 + charge
What is the charge of an ion that has 12 protons and 13 electrons?
What is the charge of an ion that has 54 protons and 52 electrons?
What is the charge of an ion that has 29 protons and 32 electrons?
What is the charge of a SR ion that loses two electrons?
What is the charge of a Fluorine atom that gains one electron?
What is the charge of an Oxygen ion that gains two electrons?
Now for some practice• Complete the back page of your
notes by your self.• When the timer is up, partner up and
share your answers.• Work together to make sure you and
your partner agree on every answer.• We will go over this as a class
POGIL: Ion Formation• Complete the Ion formation activity
with your group members• Hand in your sheet when completed• If you finish early you may work on
your homework until time is up.
Chemical Bonding
Electron Review• The electron configuration shows the location
of all of the electrons in an atom• Valence electrons are the electrons in the
outer most shell• Valence electrons are represented in Lewis Dot
Structures• The charge of a particular atom can be found
by subtracting the number of electrons (given by the electron configuration) from the number of protons (given by the atomic number)
2-8-8-1
Noble Gas Configuration• Elements will gain
or lose electrons to obtain a noble gas configuration (full outer shell).
• Metals tend to lose electrons
• Nonmetals tend to gain electrons
Current Electron Configuration
After losing an electron
Nobel gas configuration2-8-8
e-
Energetically Stable• By achieving the noble gas
configuration, the atom becomes more energetically stable (reaches a lower energy state).
Gaining or Losing Electrons•When an electron is gained or lost, it isn’t being pulled out of air or released into space. • Electrons are always taken from or given to other atoms.
Bonding• When electrons are transferred,
shared or pooled between atoms, a bond is formed.
• A bond represents increased stability between two atoms.
Spectrum of BondingThere are many different types of bonding.
Electron Transferred
Electron Shared
Electron Attracted
Ionic Bonding
CovalentBonding
IntermolecularBonding
MetallicBonding
Types of Bonding• Ionic Bonding: when electrons are
transferred between atoms (Metal and Nonmetal)
• Metallic Bonding: when electrons are pooled among atoms (all Metal)
• Covalent Bonding: when electrons are shared between two atoms (all Nonmetals)
• Intermolecular bonding: When an atom is attracted to electrons in another molecule (between covalent molecules)
Ions Quick Facts• When do ions gain or lose?
- 1, 2, or 3 valence electrons will lose those electrons - 5, 6, or 7 valence electrons will gain electrons
• Always want to get to a full outer level (usual 8 electrons)
• To find overall charge:– 1. Add the number of protons– 2. Add the number of electrons when in balanced state– 3. Add/sub the number of electrons changing by (lose =
subtract; gain = add).– Remember: electrons are NEGATIVE– Answer should be: -3, -2, -1, 0, +1, +2, +3. Rarely will you
have a charge grater than 3.
Ions Con’t• To write the notation of an ion:
1. write the element symbol2. in the upper right corner write
the chargePractice: Li F O• Atoms that gain electrons are cations• Atoms that lose electrons are anions
Ionic Bonding• In ionic bonding, the electron is
completely transferred from one atom to another.
• Both atoms become charged ions.
Na Cl+ -
Ionic Bonding
MgCl+
-
Cl-2
Positive ions will lose all electrons. Negative ions will gain until they have 8.If need be, an atom will give away electrons to many different atoms
PracticeDraw Lewis Dot diagrams for each
of the following atomic pair and show electrons transferred.
Na and FAl and ClNa and O
Do Now: Update TOC1. Ion Formation2. POGIL: Ion Formation3. Atoms and Ions HW4. Chemical Bonding5. Chemical bonding
con’t6. Ionic Bonds Activity7. Ionic Bonding
Worksheet8. Naming Ionic
Compounds Notes
9. POGIL: Naming Ionic Compounds
9-a POGIL Con’t10. Ionic Bonding Practice11. Writing Ionic Compounds Guided Practice12. Bond with a classmate13. Chemical Bonding
Ionic Formulas• Formulas represent the
number of ions that are involved in bonding.• In the formula MgCl2, one
magnesium atom is ionically bonded with two atoms of chlorine. • In the formula NaCl, one
sodium atom is ionically bonded with one atom of chlorine.
Formula WritingWhen writing formulas for ionic
systems, always write the cation (positively charged ion) first.
MgCl2 Cl2Mg
Writing Ionic Compound Formulas• Find the two
elements (metal and Non-metal) on the periodic table.
• Write their oxidation numbers above.
• Criss Cross • Reduce
B F3+ 1-
BF3
Boron Fluoride
Nature of ionic Bonds• Charged atoms
are attracted to opposite charges much like magnets are.
• However, nothing more is holding the atoms together.
+
-
Formula Units• Since no ion is
specifically bonded with another ion, we cannot refer to ionic compounds as molecules.
• Instead, we refer to ionic compounds as formula units (the ratio of cations to anions in the solid).
Bonding Basics Activity• One group member come get a
“white board”• One group member get a marker• One group member get counters• Take out the Bonding Basics Sheet• Wait for further instructions
Completing the chart
Completing the Ionic BondsStep 1- Write the Element Symbols on white boardsStep 2- Add counters to create Lewis StructuresStep 3- Move the electron to complete the shellStep 3- Draw a model like the one to the right on your paper that represents what you did on the white boardStep 4- Write the notation for each ionStep 5- Write the equation for the new compound made by the ionic bond
Naming Ionic Compounds
Chloride
Binary Compounds• For ionic compounds consisting
of two types of atoms…
NaClThe cation is given
the element
name
The anion is given the element
name ending in -
ideSodiumChlorine
Common Anions• Sulfur = Sulfide• Oxygen =
Oxide• Phosphorus =
Phosphide• Nitrogen =
Nitride• Fluorine =
Fluoride• Chlorine =
Chloride• Carbon =
Carbide• Arsenic =
Arsenide• Sellenium =
Selenide• Bromine =
Bromide• Iodine = Iodide
What is the name for NaP?
1. Sodium Phosphorus
2.Sodium Phosphide
3.Sodide Phosphide
4.Sodide Phosphorus
What is the name for MgO?
1. Magnesium Oxygen
2.Magenide Oxide
3.Oxygen Magnenide
4.Magnesium Oxide
Polyatomic Ions• Some ions are composed of multiple
atoms covalently bonded together• These groups of ions are called
polyatomic ions[OH]-Hydroxide
Polyatomic Ions
What is the formula for Sodium Hydrogen Carbonate?
1.NaHC2.Na2HCO3
3.NaHCO3
4.NaHCO2
Ions with multiple charge states• Some elements have
multiple charge states possible.
• To designate the charge of these ions in the formula name, we use roman numerals.
Roman Numerals
•1 = I•2 = II•3 = III
•4 = IV•5 = V•6 = VI
Examples Consider the following name:
Copper (II) Chloride
Cu Cl
Consider the following name: Chromium (VI) Oxide
Cr O
Practice
What is the formula for Iron (II) Oxide?
1.Fe2O2.FeO3.FeO2
4.Fe2O2
What is the formula for Vanadium (V) Bromide
1.VBr3
2.V3Br3.VBr5
4.V5Br
Writing Ionic Compounds
Be O2+ 2-
BeO
Beryllium Oxide
SIMPLIFY
Writing Ionic Compounds
Na PO41+ 3-
Na3PO4
Sodium Phosphate
Writing Ionic Compounds
Fe CN2+ 1-
Fe(CN)2
Iron (II) Cyanide
What is the formula for Potassium Hydroxide
1.KH3O2.KH3.KO4.KOH
What is the formula for Dimercury (I) Fluoride
1.HgF2.Hg2F3.HgF2
4.Hg2F2
Do Now- •What is an ionic bond? State 2 key aspects.•When do we use roman numerals?•Why do atoms form bonds?•Why can’t we have negative numbers after criss-crossing?
Covalent
Bonding
http://www.chemistrydaily.com/chemistry/Double_bond
Shared ElectronsCovalent bonds are about sharing electrons.
*Also called molecular bonds*
Shared Electrons• Atoms share electrons to
have access to electrons to achieve a noble gas configuration.
• Neither atom wants to lose its electrons.
• They engage in a “tug of war” over the electrons.
F
He-
Drawing Bonds• When two electrons are shared between
two atoms, this bond is represented as a line.
FHe-
e-
e-e-e-
e-e-
e-Hydrogen wants to gain 1Fluorine wants to gain 1
Non-bonding Electrons
FH
Electrons not involved in bonding are referred
to as Lone Pairs of Electrons
Drawing Covalent Molecules• Drawing covalent molecules are
a bit more complicated than ionic formula units.
• Atoms are now bonded to specific atoms within the system.
• We can represent these bonded systems through Lewis Dot Diagrams.
Lewis Dot Diagrams
O OFirst, draw the valence electrons
Second, connect the single electrons
Lewis Dot Diagram
O OThird, put bonds directly between atoms
Lewis Dot Diagram
NCl
ClCl
Lewis Dot Diagram
CO ClH
Independent Practice• Draw Lewis Dot diagrams and bonds
for the following molecules.
CH4NF3 H2O CO2
Do Now-Update TOC14. SH1015. Ionic Bonding Overview16. Review Naming Ionic Compounds17. Covalent Bonds Notes18.Venn-Diagram and Vocab19.Bonding Basics- Covalent Bonds20.Bonding Basics Packet21.Molecular Geometry22.Covalent Bonding Practice
Homework Check
Molecular Geometry
Electron Repulsion• When we draw structural
formulas using Lewis Dot diagrams, we can’t always see the exact angles of the bonds.
• However, what we know is that the electrons want to be as spaced out around the center atom as much as possible.
CO
Cl
H
Geometries In order for the electrons to
get as far apart as possible, the
atom’s orbitals adopt a geometry that
minimizes their interaction
But how do you know?By drawing Lewis Dot
Diagrams, you can predict
the geometry of a molecule.
CTetrahedral
Molecular GeometryThere are four basic
geometries.
Linear
Pyramidal
Tetrahedral
Bent
Example with Oxygen
O Bent
Example with Chlorine
ClLinear
Check your work on the geometry notes page
Bond Energy
Bond Energy• Each level of electrons have energy• Levels closer to the nucleus have less
energy than the levels further away• When atoms form bonds, the atoms
become more energetically stable. • The energy required to make or this
bond is referred to as the Bond Energy.
Bonds and Energy• By forming this
bond, the atoms become more energetically stable.
• Energy is released. • The atoms get
their “stable 8” configuration and can relax.2Mg + O2 2MgO
Bonds and Energy• When a bond is broken,
energy is absorbed.• The energy required to
break this bond is referred to as the Bond Energy.
• When atoms are separated, they lose their “stable 8” electrons.
• The potential energy of each atom is decreased.
http://durangotexas.blogspot.com/2010/06/crowley-texas-school-bunsen-burner-gas.html
H Cl
Do Now- Use your notes if need be. Remember to check to see if these are
ionic or covalent!• Write the name of the following:1. NH3
2. FeSO4
3. CoBr2
• Write the formula for the following:1. Vanadium (V) Oxide2. Aluminum hydroxide3. Silver Phosphate
Polarity
Molecular Geometries and Sharing Electrons
• In a covalent bond, two atoms are sharing electrons. • Just like in the real world, they don’t
always share equally. • Electronegativity: The attraction that
an atom has for electrons in a bond• Electrons spend more time with the
greater electronegative atom
Consider Hydrogen Fluoride (HF)
H FWhat is the electronegativity of
each atom? Check Table S in your NYS Reference Tables
2.1 4.0e-e- δ-δ+
Polar Bonds• Where one atom has a higher
electronegativity than the other, there is an unequal sharing of electrons.
• The unequal sharing of electrons in a covalent bond will result in the formation of a polar bond.
• Polar bonds have partial positive (δ+) and partial negative (δ-) charges.
Is the bond between Carbon and Hydrogen polar?
Is the bond between Hydrogen and Hydrogen polar?
Is the bond between Hydrogen and Tellurium polar?
Which bond is more polar, N-H or C-H?
Which bond is more polar, O-N or H-O
Practice• Let’s consider….
Si – O δ-δ+
Intermolecular Forces
Polar Molecules• Within a molecule, each bond can be
polar or nonpolar.
CH
H
H
H
Molecular Polarity• The net polarity of a molecule is
dependent upon the orientation of the polar bonds.
CH
H
H
H
In the case of CH4, each bond is polar. Because methane has a tetrahedral geometry, each polar bond cancels out the adjacent bond.
Non-polar MoleculesWhere all polar bonds cancel
out, the molecule is considered
non-polar.
CH
H
H
H
Polar Molecules
Where the polar bonds don’t cancel
each other out, the molecule
becomes polar.
N HHH
δ-
δ+δ+
δ+
Consider…H2S
δ-
δ+δ+
Consider…CO2
Non-Polar
How does a bond’s polarity impact a molecule and its
behavior?
H
HOSi
δ+
δ+
δ-
Intermolecular Forces
Intermolecular ForcesThe presence of partial positive
and partial negative
charges allow for the
interaction of molecules.
δ-δ+
Intermolecular ForcesThe partial positive and
negative charges are called dipoles.
Molecules with dipoles can experience dipole-dipole
attractions.
Dipole-Dipole Interactions In solution, these molecules will orient themselves so that the
positive dipole is near the negative dipole of another molecule.
Hydrogen BondingWithin dipole-dipole
interactions there is a subset of stronger
interactions called hydrogen bonds.
Intermolecular bonds between hydrogen and F, O,
N, Cl.
What about Non-polar molecules?
H
H
H
H
Van der Waals/London Dispersion Forces
The molecule is surrounded by the electron cloud.
+-
--
Molecules can now be attracted to one another temporarily
Van der Waals/London Dispersion ForcesJust like a real cloud, the electron cloud moves around the molecule.
Van der Waals Forces• What would increase the
strength of Van der Waals forces?–The size of the electron cloud–The size of the molecule–The composition of the molecule
Boiling Point and Van der Waals Forces
C5H12 C6H14 C7H16
C8H18
What type of intermolecular forces best describes NH3?
1. Dipole-Dipole Interactions
2. Van der Waals Forces
3. Covalent Bonds4. Ionic Bonds
What type of intermolecular forces best describes CH3CH3?
1. Dipole-Dipole Interactions
2. Van der Waals Forces
3. Covalent Bonds4. Ionic Bonds
What type of intermolecular forces best describes PCl3?
1. Dipole-Dipole Interactions
2. Van der Waals Forces
3. Covalent Bonds4. Ionic Bonds
What type of intermolecular forces best describes CH3OH?
1. Dipole-Dipole Interactions
2. Van der Waals Forces
3. Covalent Bonds4. Ionic Bonds
Hydrogen
Hydrogen BondingBecause the polarity of bonds
between hydrogen and F, O, N, (Cl) is so great, the attraction between these dipoles is more intense.
Hydrogen Bonding and Boiling Point
The Special Nature of Water• The difference between water as a
bent structure and water as a linear structure is the difference between life and death on the planet.
What we know about water…
• It has a bent geometry. • It is a polar molecule. • It experiences dipole-dipole/hydrogen bonding.
Giver of Life• The human body is approximately 60% water. • If water didn’t hydrogen bond, what would be the consequences for life?
Modern Marvels: Water
Start at 15:23
Crystal Structure of Water• Because of hydrogen bonding, the
water molecules arrange into a specific geometry.
Crystal Structure of Water
• The orientation of water molecules in a solid form take up more space than the liquid form.
• Solid is less dense.
Thus, ice floats.
Walking on WaterThe ability for
water molecules to hold
together, seemingly
forming a skin is referred to as
surface tension.
Surface Tension The molecules on
the surface of water feel the pull back into the liquid and
the pull of their neighbors, creating
a “skin” on the water.
How would life be different?• If water was non-polar…–Grab a large whiteboard, make a
poster that describes how life would be different if water was a linear, non-polar molecule. –These are predictions based on
what you know and what you see in the Modern Marvels' video