Covalent bonding forms ______ by ______ electrons and covalent bonds are ______ than Ionic bonds because ________.
molecules, sharing, weaker, ionic bonds involve a complete transfer of electrons between a cation and anion (meaning there are huge electrostatic forces of attraction) while in covalent electrons are just being shared not transferred.
What is used to predict the shapes of molecules?
Lewis structures and VSEPR (Valence Shell Electron Pair Repulsion) theory (based on the idea that electron groups repel one another)
What are some properties of ionic bonding?
They form crystal and salts, solids at 22 degrees C. They're melting point is higher because their bonds are stronger. When solid, not good conductors, when liquid or dissolved in liquid good conductors (they can conduct electricity as they are charged ions but ONLY when the electrons can move like in a liquid state). They are also brittle and cannot be formed into shapes with force.
What are physical properties?
properties that can be determined with the five senses, they are a description;color, taste, state of matter, boiling/freezing/melting point.
What are the types of reactions?
1. synthesis (A+B-->AB)
2. Decomposition (AB-->A+B)
3. single displacement (AB+C-->CB+A)
4. Double displacement (AB+CD-->CB+AD)
5. Combustion (_____--> H20+CO2)
Write the steps of drawing a Covalent Lewis Structure:
1. Write correct skeletal structure for molecule (H, O).
2. find the total number of valence electrons. (H has 1, O has 6)
3. Distribute the electrons among the atoms, filling octets, 8 (or duets, 2 for hydrogen)
4. If any atoms don't have octet, form double or triple bonds (whatever necessary) to give them octets
What are 5 possible Molecular Geometry types?
Liner, Trigonal planar, tetrahedral, bent, trigonometrical pyramidal
What are some properties of Covalent bonding?
They form soft solids, their melting and boiling points are low as their bonds are weaker than ionic, and they do not conduct electricity in any phase because their molecules are neutral as covalent bonds do not transfer electrons, so there are no charged particles.
What is the difference between an Extrinsic and Intrinsic property? Give examples of both.
An extrinsic property depends on the amount of matter present (volume, mass, amount of energy) while an intrinsic property is not dependent on the amount of matter (density, ability to conduct electricity, melting/freezing/boiling points).
What type of reaction is V+CuCl2? What is oxidation and reduction? Which was oxidized and reduced?
Single displacement
If its oxidized it loses electrons if its reduced it gains electrons
V oxidized (0 to +2), Cu reduced (+2 to 0).
True or false: Covalent bonding occurs between metals and nonmetals
False: that's ionic bonding, covalent bonding occurs between nonmetal and nonmetal elements
How many electron groups are in NH3? What molecular geometry does it have?
4, trigonal pyramidal
How do you determine the Polarity of a Molecule?
1. Draw the correct VSPER shape (lewis structure in the molecular shape)
2. Determine if bond is polar or nonpolar by subtracting electronegativity and putting dipole arrow toward more electronegative atom.
3. Look for symmetry (not symmetrical--> polar, symmetrical--> nonpolar)
What are chemical properties? What are some examples?
properties that are determined by a substance's ability to react with another substance. rust (ability to react with air) flammability, etc.
What are oxidation states and the rules for determining oxidation number?
Oxidation states = # assigned to atoms that represent net charge of an atom if electrons in chemical bonds (involving that atom) were assigned to more electronegative atoms (closer to stable configuration 8 electrons in valence shell).
Rules
1. Simple ions (Na +1 )= ionic charge (1)
2. Hydrogen = +1, in hydrides = -1
3. Oxygen = -2, not in peroxides
4. Uncombined element (Cl, N2) = 0
5. Compounds net charge (CO2) = 0
6. Polyatomic ions combine to form specific charge of ion (SO4-2) (S has to be plus 6 as O is -8, 6-8=-2)
When do Resonance structures occur? What's an example?
Resonance structures occur when there are multiple Lewis structure that can be drawn (true) for one molecule. An example is NO3-1
What do A X and E represent in AXE notation?
A --> Central Atoms
X --> Terminal Atoms
E --> Free electron Pairs
What's the difference between intramolecular forces and intermolecular forces?
intra occur within a molecule and examples are covalent, ionic and metallic
inter occur between molecules and are weaker than intra, and example is a hydrogen bond
A physical change is one that occurs without ______ of the substance and ______ substances are formed. While in a chemical change, the identity of the substance is_____ and _____ is formed with _____ properties.
changing the identity, no new, changed, a new substance, new
In order to convert grams to liters you must first convert grams to ________ which are equal to ____________. M represents_______
moles
22.4L, atomic mass of whatever element/compound you have (in grams), and 6.02x1023 atoms
moles of solute per volume (liter)
What's the difference between naming Ionic versus Covalent compounds?
Covalent compounds don't use roman numerals and prefix is used to denote the number of atoms in EACH element in the compound (but mono meaning one is not used on the first atom).
You have SnCl2. What is it's AXE notation? How can it be used to find the molecular geometry?
SnCl2-->AX2E (There is one central atom Sn, there are two terminal atoms or atoms bonded to A, and there is one lone pair) Using this information you know it will either be bent (molecular geometry where lone pairs' influence is taken into account) or trigonal planar (where it is determined only by how many groups - electron pairs - there are)
What is the result of uneven electron sharing?
The result of uneven electron sharing is a dipole moment which is a separation of charge within the bond.
A bowl of water is boiled, the water vapor lands on the cold window and condenses. Is this a chemical or physical change?
Baking soda and vinegar are mixed. Is this a chemical or physical change?
Sugar is dissolved in/mixed with water. Is this a chemical or physical change?
physical, no new substance produced, can be reversed
chemical, a reaction occurred and new substances were formed, can't be reversed
physical, no new substances, can be reversed
What is needed in order to convert from moles to moles? Where is this information found?
Mole ratio, Balanced chemical equation