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Name Chem RG Chapter Packet 6 – Covalent Compounds
Period.
Assign Section # Name 10 5
1. Assignment Sheet printed
2. Notes 6.1
3. Notes 6.2
4. Notes 6.3
5. 6.1 Covalent Bonds (WS 4.6 Polar Bonds & electronegativity)
6. 6.2a Ionic Bonding Interactive Activity PBSLearning (2 pages)
7. 6.2b Lewis Dot diagrams WS 5-7
8. 6.2c WS 4.5 More Lewis Structures
9. 6.2d Naming Molecular Compounds WS 9-2
10. 6.3 Molecular Shapes WS 9-6
11. Unit Conversion Tutorial Part 3
Ch 06 Test Review (turn in separately for graded points)
(Total Points = 11 x 10 = 110)
Notes:
1. Your lab report is turned in by itself and receives a separate grade. 2. Your test reviews are graded separately. 3. Website: http://chem-rg-flipped.santiago.groupfusion.net/
EVIDENCE (after you take notes.) You should have at least 4 types of evidence for each set of notes. 1. Number new concepts 1,2,3…/A,B,C… 2. Delete/Cross out unimportant information Unimportant
3. Circle vocab/key terms
4. Identify points of confusion ?
5. Underline/Highlight main Ideas Main Ideas 6. Identify information to be used on a test, essay… *
7. Fill in gaps of information. Reword or paraphrase. ^ 8. Create visuals/symbols of important
information Visuals/symbols
Key Terms
Ch 6 B10 Relative Solubilities of the Transition Elements Transition elements are in periods 4, 5, and 6 (between groups 2 & 13). As the atomic number increases across a row in this section of the table, no new valence electrons are added. Instead, electrons are added to inner energy levels. So, transition element properties are similar across a row as well as down a column. Often, the properties of transition element properties in a row are more alike than in a column. This is not so for non-transition elements.
In this lab, you will evaluate the solubility of compounds of iron, copper, zinc, and silver in both water & acid. Iron, copper, and zinc are in the same row of the periodic table; copper and silver are in the same column. You will mix these transition elements with five different reactants and observe whether an insoluble compound (precipitate) forms. For those that form precipitates, you will investigate how the precipitate behaves in acid. After recording your findings, you will decide whether each new compound is soluble or insoluble in water and to what extent it dissolves in acid. You can then look for trends related to the positions of the elements in the periodic table. OBJECTIVES • Observe the reactions of some transition-element ions with five anions.
• Deduce the solubility of transition-element compounds in water and in acid. • Compare solubilities of elements in same column and in the same row of the periodic table.
PROCEDURE - See ast page of lab for helpful notes
CAUTION: Nitric acid, HNO3, is corrosive and caustic. Avoid contact with eyes and skin. If any should spill on you, immediately flush the area with water and notify your teacher. 1. Copy the Data Table into your lab notebook. 2. Flow-chart this procedure in your lab notebook. 3. Place two drops of each transition-element solution in the appropriate well on the microplate. These
solutions contain positive ions. Be careful; silver nitrate, AgNO3, will stain skin and clothing. There should be five boxes in a row for each transition element.
4. Add two drops of each of the reactants, which contain negative ions, to each of transition-element solution. Do not allow the dropper to touch the transition-element solutions!
5. Immediately after adding each reactant solution, record your observations in the Data Table section labeled 0 min. If no reaction occurs, write NR. If a precipitate f o r m s , record its color.
6. Wait 5 min, and then record any changes the Data Table section labeled 5 min. If no change occurs, w r i t e same. 7. To each mixture in which a precipitate formed, add 1 to 4 drops of 1.0 M nitric acid. Write “clear” in the acid
section if the precipitate disappeared. Write PC if the precipitate partially disappeared & “same” if no change. Record any color change.
8. Clean all apparatus and your lab station. Return equipment . Put chemicals & solutions in disposal containers.
Analysis Organizing Data and Analyzing Results
1. Study your Data Table ((on the next page) carefully. Then complete the Solubility Chart below it. a . Write S if the mixture is soluble in water (no reaction) b. Write PS if it is partially soluble in water. (Assume a mixture is partially soluble in water if it
was clear at 0 min but became cloudy after 5 min.) c. Write SA if the mixture is soluble in acid but not in water. d. Write PSA if it is partially soluble in acid but not in water. (Assume a mixture is partially
soluble in acid if the precipitate partially dissolved after adding nitric acid, HNO3) e. Write I if the mixture is insoluble in water and acid.
DATA TABLE:
Transition ions
Reactant ions Cl1-
C2O4
2- SO4
2-
SCN1-
Fe(CN)6
4-
Cu2+ 0 min
5 min acid
Fe3+ 0 min
5 min acid
Ag+ 0 min
5 min
acid
Zn2+ 0 min 5 min acid
SOLUBILITY CHART (fill in after the lab. Use your data table & write “S”, “PS”, “SA”, “PSA” or “I” according to the directions in “Organizing Data” #1 on the previous page ) Transition ions
Reactants Cl1- C2O4
2- SO42- SCN1- Fe(CN)6
4-
Cu2+
Fe3+
Ag+
Zn2+
Analyzing Results. 2. Which transition-element ion(s) formed the greatest number of soluble compounds? 3. Which transition-element ion(s) formed the smallest number of soluble compounds 4. Copper and silver are in the same column. Iron, copper, & zinc are in the same ro w. According to your
Solubility Chart, are solubilities more similar across the row, or down the column, or neither? 5. Use your Data Table and Solubility Chart to identify each of the following unknown (+ ) ions.
a. Forms a white precipitate with Cl1- b. Forms a precipitate with at least 4 reactant ions.
B10 Solubility Trends Lab Notes
Ch06 Covalent Compounds (Holt) pp 6.1 Covalent Bonds
• Explain the role & location of electrons in a covalent bond. • Describe the change in energy & stability when a covalent bond forms. • Distinguish between nonpolar and polar covalent bonds based on electronegativity differences. • Compare physical properties of different bond types and relate to electronegativity
Types of Chemical Bonding Ionic - results from the __________ __________ between large numbers of __________ and __________.
Covalent - results from the __________ of electron __________ between two atoms.
Metallic - from chemical attraction between __________ atoms and the ______ of e-s surrounding them.
Ionic or Covalent? Bonding atoms are rarely purely ionic or purely covalent. The % character of ionic or covalent bonding can be estimated from the __________ in electronegativities. See Fig. 6, p. 194 to solve the problems.
Types of Covalent Bonds Nonpolar - bonding electrons are shared __________, resulting in balanced distribution of electrical charge.
Polar - __________ distribution of electrical charge.
Polar-covalent bond - the bonded atoms have an unequal attraction for the shared electrons.
Differences in Electronegativity 0.0 to 0.3 -- Nonpolar-covalent (less than 5%) 0.3 to 1.7 -- Polar-covalent (5% to 50%) 1.7 to 3.3 -- Ionic (more than 50%)
Covalent Bonding & Molecular Compounds Molecule - __________ group of atoms held together by __________ bonds.
Molecular compound - a chemical compound composed of molecules.
Chemical formula - Shows relative numbers by using atomic __________ and __________.
Molecular formula - Shows types and numbers of atoms in a single molecule.
Diatomic molecule - molecule with only __________ atoms.
The electrons in each atom are __________ to the nucleus of the __________.
The electrons __________ each other, The nuclei __________ each other.
They reach a distance with the ________possible energy. The distance between is the _______ ________.
Bond Energy - energy required to break a chemical bond and form neutral isolated atoms.
The Octet Rule Noble gases don’t ________. Possess minimum energy on their own because of their e- configurations.
Outer __________ orbitals completely filled.
Octet Rule - Compounds form so each atom _______, ________or ________electrons to get an ________in its __________ __________ energy level.
Covalent Bonding
Electrons are __________ by atoms. Sharing is caring and caring is __________
There are two extremes. In between are ________covalent bonds where the e-s are _______shared evenly.
One end is __________ positive, the other __________. Indicated using small delta δ.
Covalent bonds __________ hold onto their valence electrons. They __________ give away electrons to bond.
Still want noble gas configuration. Get it by __________ valence electrons with each other.
By sharing __________ atoms get to __________ the electrons toward noble gas configuration.
Covalent is __________ to __________.
Metallic Bonds Metals hold onto their valence electrons very __________.
Think of the metals as positive ions floating in a __________ of negative electrons.
__________ are free to move through the __________. So, metals __________ electricity.
Metal Properties Malleable - can be __________ into shape. Ductile - can be drawn into ________. Shiny
6.2 Drawing and Naming Molecules • Draw Lewis structures to show valence electron arrangement in molecules and polyatomic ions. • Explain the difference between single, double, and triple bonds. • Draw resonance structures and know when they are required. • Name binary inorganic compounds using prefixes, roots and suffixes.
Keeping Track of Electrons The e-s responsible for the __________ properties of atoms are those in the __________ energy level.
__________ electrons - The __________ electrons in the __________ energy level.
Core electrons - those in the energy levels __________ (inner electrons).
Electron Dot diagrams Write the symbol. Put one dot for each valence electron. Don’t pair up until they have to.
Electron Dot Structures Symbols of atoms with dots to represent the valence-shell electrons 1 2 13 14 15 16 17 18 H• He: • • • • • • • • • • • Li• Be• • B • • C • • N • • O • : F • :Ne : • • • • • • • • • • • • • • • • • • • Na• Mg• •Al• • Si • •P• •S• :Cl • :Ar : • • • • • • • •
Write the electron dot diagram for:
Na
Mg
C
O
F
Ne
He
Single Covalent Bond
A sharing of __________ valence electrons. Only between __________
nonmetals to nonmetals = __________
__________ to nonmetals = ionic
Rules __________ the valence electrons.
Use a __________ to form a __________ between each pair of atoms.
Arrange the __________ to fulfill the __________ rule (except for H and the __________).
Can use a __________ instead of a shared pair.
Try CH3I and NH3 in the space below
Multiple Covalent Bonds Sometimes atoms share __________ than one pair of valence electrons.
A __________ bond is when atoms share two __________ of electrons (__________ electrons).
A triple bond is when atoms share __________ pairs of electrons (__________ electrons).
Carbon dioxide – COPY THE EXAMPLE INTO THES NOTES
How to draw Lewis Structures pp __________ up all the valence electrons. __________ up the total number of valence electrons to make all atoms ________. (8 for all but H) Subtract. Divide by __________ This tells you # of __________ - draw them. Fill in rest of the valence electrons so atoms get their __________ gas configuration. (happy-have) / 2 = # of bonds
Example HCN – DO THIS ON YOUR NOTES AS WE DO IT IN CLASS HCN C is central atom
N - has __________ valence electrons wants __________
C - has __________ valence electrons wants __________
H - has __________ valence electrons wants __________
HCN has 5+4+1 = __________
HCN wants 8+8+2 = __________ (to be __________)
(18-10)/2= __________ bonds
So, __________ atoms with __________ bonds - will require __________ bonds (but, not to H -- why?)
Put in the two __________ bonds
Still need 2 more bonds (to be happy)
These must go between C and N (why?)
Polyatomic Ions Charged group of __________ bonded atoms. E.g., NO3
1-, SO42-, NH4
1+.
Lewis structures: Follow __________ steps __________:
If __________, __________ electrons = to the __________. If cation, subtract e-s = to the charge. Use brackets. You Try Lewis Dot Notation PO4
3- NH41+ IBr
Cl2O ClO1-
Resonance When __________ than one Lewis diagram with the same connections are possible. Use double arrows to indicate it is the “__________” of the structures. Try NO3
1- IN YOUR NOTES HERE
Covalent Names & formulas
Easier than ionic naming and formulas Molecular compound’s name tells you the number of atoms. It uses prefixes to tell you the number. 1 mono- 2 di- 3 tri-
4 tetra- 5 penta- 6 hexa-
7 hepta- 8 octa- 9 nona-
10 deca-
To write the name write two words One exception is we don’t write mono- if there is only one of the __________ element. Write least electronegative atom first
Name these
N2O
NO2
Cl2O7
CBr4
CO2
BaCl2
Write formulas for these diphosphorus pentoxide
tetraiodine nonoxide
sulfur hexaflouride
nitrogen trioxide
Carbon tetrahydride
phosphorus trifluoride
aluminum chloride
6.3 Molecular Shapes
• Predict a molecule shape using VSEPR • Determine the polarity of a molecule from its shape.
Molecular Geometry Molecular properties depend on
(1) __________ of atoms and (2) __________.
Molecular polarity - the __________ distribution of __________ charge (vs. atomic charge).
VSEPR Theory Valence Shell Electron Pair Repulsion. Predicts 3-dimensional geometry of molecules.
The __________ tells you the theory.
Valence shell - __________ s & p electrons.
Electron Pair Repulsion - electron pairs try to get __________ as possible.
Can determine the __________ of bonds (geometry).
VSEPR Based on the number of pairs of __________ electrons both __________ and unbonded. Unbonded pairs are called __________ pairs.
4 atoms bonded to central Basic shape is __________. (AB4) A pyramid with a triangular base. Same shape for everything with 4 pairs of e-s.
3 bonded with 1 __________ pair Still basic tetrahedral, but you can’t __________ the electron pair (still takes up space). (AB3E)
So, shape is called __________ __________.
2 bonded with 2 lone pair
Still basic tetrahedral but you __________ the 2 lone pairs. (AB2E2)
Shape is called bent __________.
__________ atoms to central, no lone pair
The farthest you can the 3 electron pairs apart is 120º. (AB3)
Shape is flat and called trigonal __________.
2 atoms no lone pair With three atoms the farthest they can get apart is 180º.
Shape called __________. (AB2)
Predicting a VSEPR Structure
1. Draw Lewis structure. Do not assume the number of e- pairs. Multiple bonds count as one pair!!! 2. Put lone pairs as far apart as can. 3. Determine positions of atoms from the way electron pairs are shared. 4. Determine the name of molecular structure from positions of the atoms (vs. the electron pairs)
VSEPR Use VSEPR theory and your gumdrops to predict the shapes of . . . CCl4,
HCN,
NO31-
Molecular Polarity & Dipole-Dipole Forces Dipole - created by equal but opposite charges that are separated by a short distance. Dipole-dipole Forces: Short-range forces of attraction between polar molecules.
We see these in __________ covalent bonds.
Polar Molecules Molecules with a slightly positive and a slightly negative end Requires two things to be true 1. The molecule must contain polar bonds (determine from differences in electronegativity). 2. Symmetry cannot cancel out the effects of the polar bonds. (Must determine geometry first.)
Polar Molecules 98% of the time, the molecule is polar if it has _________bonds & there is at least one __________ pair. Is it polar? Draw the structure and follow the rule just above. HF H2O NH3 CCl4 CO2
6.1 Worksheet: Covalent Bonds Use the electronegativity table in your notes (or see p. 194) and the bonding rules (see your notes).
Atoms Electronegativity Difference
Bond type (Ionic, polar covalent or nonpolar covalent)
Most electronegative atom
H and I
S and O
K and Br
Si and Cl
Se and S
C and H
6.2a Ionic & Covalent Bonding Interactive Activity PBSLearning (2 pp.) Go to http://www.pbslearningmedia.org/shared/blachman/chemsharks/
Ionic Bonding, also do Covalent Bonding
Ionic Bonding Interactive Activity Charges that are alike will __________each other whereas charges that are opposite will ________ each other.
Therefore, ionic compounds need both a ______________ ion and a ___________ ion.
_______________ usually make positive ions and _____________ usually make negative ions. Therefore,
ionic bonds are usually formed when _____________ bond with _____________.
When sodium loses an electron it becomes a _______________ charged ion.
When chlorine gains an electron it becomes a ____________________ charged ion.
These two ions are held together because of their ________________ charges.
In ionic compounds the formula tells us the _______________ between the ions in the crystal. It does not
mean that they are individual _______________________.
Covalent Bonding Interactive Activity How do the hydrogen atoms interact with each other? __________________________________________
________________________________________________________________________________________
How is the movement of the electrons different when you move the atoms close to each other?
________________________________________________________________________________________
What happens if you try to move the atoms very close to each other? ____________________________
________________________________________________________________________________________
Where do the shared electrons spend most of their time? _______________________________________
In a covalent bond both atoms ______________ or _______________ over the electrons.
In general, covalent bonds tend to form between______________.
Atoms are most stable when what two things occur? ___________________________________________
________________________________________________________________________________________
When atoms share two pairs of electrons we call it a _____________ bond, where a total of
________________ electrons are shared.
When atoms share three pairs of electrons we call it a _____________ bond, where a total of
________________ electrons are shared.
When atoms share one pair of electrons we call it a _____________ bond, where a total of
________________ electrons are shared.
The strongest bonds are usually _____________ bonds and the weakest bonds are usually
________________bonds.
When naming a covalent bond the ending of the second element is usually changed to __________.
Why are prefixes added to an elements name? _______________________________________________
mono- means _____ di- means _____ tri- means _____
tetra- means _____ penta- means _____ hexa- means _____
What is the only exception when using a prefix when naming a covalent compound?_______________
________________________________________________________________________________________
__
Give the name for the following: Give the formula for the following:
N2O ____________________________ disulfur dichloride __________
NO2 ____________________________ sulfur dioxide __________
N2O4 ____________________________ disulfur trioxide __________
N2O3 ____________________________ disulfur monoxide __________
NO ____________________________ sulfur trioxide __________
6.2b Worksheet: Drawing and Naming Molecules (Lewis dot Diagrams, Chem Worksheet 5-7)
6.2c Worksheet: More Lewis Structures Draw the following covalent compounds using Lewis Dots (Use “happy – have ÷ 2)
a. CH4 b. H20 c. NH3
Double Bonds…..(4 e-‘s are being shared or 2 bars) Be sure to balance & pair up the lone pairs! d. N2F2 e. 02 f. C02 (2 sets of double bonds!) Triple Bonds…..(6 e—‘s are being shared or 3 bars) Be sure to balance & pair lone pairs! g. N2 h. HC2Cl i. C2H2 Ions Lewis Dots j. F- k. Mg2+ l. P3- Polyatomic Ions
m. SO42- n. H3O+ o. NH4
+ Resonance (Show BOTH ways the Lewis Dots can be shown)
p. O3 q. SO2
6.2d Worksheet: Naming Molecular Compounds (Chem Worksheet 9-2)
6.3 Worksheet: Molecular Shapes (WS 9-6)
Draw the Lewis structure and use VSEPR to predict the shape of the following: Formula Lewis Structure Shape (happy-have) / 2 = # of bonds NH2Cl NOCl (N is central atom double bond between N & O) NO3
1- NH4
1+
Unit Conv. Tutorial Part 3 Name: ______________________________ Period: _______
• Go to the following website: http://joneslhs.weebly.com
• Click on the Learn button on the left. Read the 5-‐minute tutorial first. When you think that you understand the idea, go back to the Main Menu and click on Double Unit Conversions and then on Cubed and Square Conversions and complete this worksheet.
• Read the directions on the first problem to see how to get started. Work through the challenging
problems recording your answer below for each one. Don’t forget units! Check your answers online on the website. SHOW YOUR WORK!
Double Unit Conversions 1. Calculated Answer:
2. Calculated Answer:
3. Calculated Answer:
4. Calculated Answer:
5. Calculated Answer:
6. Calculated Answer:
Cubed and Squared Conversions 1. Calculated Answer:
2. Calculated Answer:
3. Calculated Answer:
4. Calculated Answer:
Name ___________________________________________ Period ________
Chapter 6: Review -‐ Turn in Separately for Points – Hint: Look at skeleton notes
The electrons are involved in bonding are called the _________________ and can be found in the _____ and _____
orbitals
The chemistry (reactivity) of an element is mostly determined by the number of ____________ electrons
For the main group (groups 1-‐2, and 13-‐18) elements, the number of valence electrons can be determined by the
_______________ number.
Molecular compounds have ___________ bonds because their electrons are _____________ between them. This
means that they will have ________ melting and boiling points. Elements in a covalent compound are often
found on the _______ side of the periodic table and occur when a ____________ bonds to a _____________.
They never conduct electricity and therefore make good ______________s.
Metallic compounds, have ___________ bonds because their electrons are _______ between them like a ______ of
electrons. This means that they will have ________ melting and boiling points. Elements in a metallic
compound are often found _____________ on the periodic table and occur when a ____________ bonds to a
_____________. They always _______ electricity. They are often shiny, ______________ (which means that
they can be hammered into sheets), and ductile, which means they can be drawn into a ____________.
In covalent compounds the formula does indicate the number of each atom that is present. Because you cannot
predict a covalent formula in the same way that you can predict an ionic formula, it is necessary to use _____________
in the name to indicate the number of each atom in the bond. However, the basic naming rules still apply, therefore,
the name of the first element still stays the ________ and the name of the second element still ends in ________.
Large biological molecules often have the element, _________, as their center atom and are made up of
____________ bonds.
Determine the bond type for the following compounds: Ionic (I), Covalent (C) or Metallic (M)
CaCl2 ________ NH3 ________ Cl2 ________ CF4 ________ Li2S ________ Cu ________ Ba(OH)2 ________
Which of the above has the lowest boiling point? (hint: think of type of bonding):
Draw the Lewis Structure for the following atoms:
Li Be B C N O F Ne
When drawing a Lewis Structure, a lone pair means those electrons are not __________ to another atom.
When one pair of electrons is shared between two atoms it is called a __________ bond, two shared pairs make up a
__________ bond and three shared pairs make up a _______________ bond.
Draw the Lewis Structure for the following compounds:
CO NH3 C2H4 SO42-‐