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Chemistry Honors Chapters 7 and 8
There will be repetition, because I just copied this from the note packets.
Terms in this set (106)
the electrons responsible fro the chemical properties of atoms, the s and p electrons in the outer energy levels, largely determine the chemical properties of an element, usually the only electrons used in chemical bonds
those electrons in the energy levels below the outer energy level
same number of valence electrons
Atoms in the same group have the ____________________________________ or the same outer electron configuration.
the attractive force between atoms or ions, formed when 2 atoms share electrons or when electrons are transferred from one atom to another
When chemical bonds are formed, energy is released. This is an _____________ reaction.
When chemical bonds are broken, energy is absorbed. This is an _____________ reaction.
electron dot diagrams
__________________________ are a way of showing and keeping track of valence electrons. You write them by writing the element's symbol (it represents the nucleus and core electrons and put one dot for each valence electron (8 maximum). Electrons don't pair up until they have to (Hund's Rule). Remember the s and p orbitals. S fills before p.
Noble gases are ____________ in chemical reactions.
the Octet Rule
In forming compounds, atoms tend to achieve a noble gas configuration, 8 in the outer shell is stable. Each noble gas (except He) has 8 electrons in the outer level.
Metals ________ electrons to attain a noble gas configuration.
When metals lose electrons, they form positive ions known as _______.
Metals have ______ valence electrons.
______ dots are shown for a cation in an electron dot diagram.
You name a cation by taking the name of the element and writing _________ after it.
Nonmetals ______ electrons to attain noble gas configurations.
When nonmetals gain electrons, they form negative ions known as _________.
ions from chlorine or other halogens that gain electrons
Anions are named by adding _____ to the end of the name of the original element.
Nonmetals have ________ valence electrons.
noble gas electron configuration
All atoms try to achieve a ____________________________________.
force of attraction that holds oppositely charged ions together, this force of attraction is formed through the transfer of electrons, electrons are transfered to achieve the noble gas configuration, anions and cations are held together by opposite charges, the resulting compound of this force of attraction is an ionic compound
_________________________ are electrically neutral. They are compounds of metals and nonmetals.
the most common ionically bonded substances
The difference in electronegativity between atoms in an ionic compound must be _________ or greater.
The _________ electronegative atom in an ionic compound takes the electron.
Ionic compounds are ________ conductors of electricity.
Ionic compounds have very ________ melting points.
To write the electron dot diagram for an ionic compound, look up the ____________________ of each of the elements on the periodic table. Write down the two symbols and the top oxidation state in the upper right hand corner. Crisscross the oxidation states as subscripts in the bottom right hand corners to determine how many of each element is present. Reduce the subscripts if possible. Do not reduce the charges. If the subscripts are one, there is no need to write them. If the oxidation states are one, just write the charge. Draw dots around the anion.
The _________________ shows the kinds and numbers of atoms in the smallest representative particle of the substance.
Ionic compounds exist as a collection of positively and negatively charged ions arranged in _________________________.
Chemical formula refers to a ratio known as a ____________________. The _____________________ is the lowest whole number ratio of ions in an ionic compound.
Ionic compounds are ______________________. There is a regular repeating arrangement of ions in the solid. Component ions in crystal are arranged in repeating 3-dimensional patterns.
Ions are ____________ bonded together. Their structure is rigid. They have high melting points. They have a very stable structure.
allowing charges to move
In a solid, the ions are locked in place. They do not conduct electricity. Ionic solids are ____________.
When ____________, the ions can move around. ________ ionic compounds conduct electricity.
Dissolved in water
_____________________, ionic compounds conduct electricity. Ions are free to move in aqueous solutions.
When melted or dissolved, the regular crystal structure of an ionic compound breaks or ______________.
The ions are free to move when they are __________ (or in aqueous solution - dissolved) and they are able to conduct electric current.
Metals are made of __________________ cations rather than neutral atoms.
The force of attraction that holds metals together are called _____________________. ____________________ consist of the attraction of the free-floating valence electrons for the positively charged metal ions. One or more valence electrons become detached from the atom and migrate in the "sea" of free electrons among positive metal ions.
"sea" of valence electrons
The valence electrons of metal atoms can be modeled as a _______________________________. Metals hold on to their valence electrons very weakly therefore the valence electrons are mobile.
In a metallic bond, electrons are free to move through the solid. This explains many physical properties of metals. Metals ____________ electricity because the electrons can flow freely in them.
Metals are malleable (they can be hammered into shape or bend. They are also __________. This means they can be drawn into wire. The malleability and the __________ are explained in terms of the mobility of the valence electrons. A sea of drifting valence elctrons insulates the metal cations from one another so the cations do not repel each other.
mixtures of 2 or more elements (at least 1 is a metal), made by melting a mixture of ingredients then cooling
Properties of alloys are often superior to the ________________. Sterling silver (92.5% Ag, 7.5% Cu) is harder and more durable than pure Ag, but still soft enough to make jewelry and tableware.
____________ are very important alloys. Their superior qualities include corrosion resistant, better ductility, hardness, toughness, and lower cost.
an alloy of Cu and Zn
an alloy of Cu and Sn
__________________ share electrons, they are different from ionic bonds because atoms actually form molecules when two specific atoms are joined
The resulting particles of covalent bonds are _____________. Many elements found in nature are in the form of _______________. ______________ are neutral groups of atoms joined together by covalent bonds. They can be found as single discrete units as opposed to ionic compounds. Compounds composed of molecules are called molecular compounds.
While the molecular formula shows how many atoms of each element are present, the _______________ shows the arrangement of these atoms.
_____________________________ tend to have relatively low melting and boiling points. Thus, they tend to be gases or liquids at room temperature. They are composed of 2 or more nonmetals. They have molecular formulas.
_________________________ show the actual number of atoms of each element a molecule contains.
__________________________ tend to have relatively high melting and boiling points. Thus, they tend to be solids at room temperature. They are composed of metals and nonmetals. We use formula units to show the lowest ratio of elements in an ionic compound. The actual number of atoms is a multiple of this ratio.
molecules consisting of 2 of the same atom, the elements that make diatomic molecules are H, N, O, F, Cl, Br, and I
Diatomic molecules share the electrons. They have a covalent bond.
Nonmetals _____________ to their valence electrons. They can not give away electrons to bond, but they still want a noble gas configuraton. Nonmetals achieve a noble gas configuration by sharing valence electrons with each other. By sharing electrons, both atoms get to count the electrons toward a noble gas configuration.
A combination of atoms of nonmetals and ____________ (groups 14-17) are likely to form covalent bonds. There are 2 types of covalent bonds, polar and nonpolar.
__________ covalent bonds form when atoms with different electronegativities share electrons. Electronegativity difference between 2 atoms in _______ covalent bonds is 0.5 to 1.7. Electrons are not shared equally.
In polar covalent bonds, the atom with the higher electronegativity gets the slight ___________ charge and the atom with the lower electronegativity gets the slight positive charge.
______________ covalent bonds form when 2 atoms with he same (or similar) electronegativity value share electrons. The electronegativity difference between 2 atoms in a nonpolar covalent bond is 0.0 - 0.5. The electrons are shared equally.
A sharing of 2 valence electrons can happen between two nonmetals or a nonmetal and a _____________. ______________ can behave as a metal and donate electrons or behave as a nonmetal and accept electrons. It usually behaves as a nonmetal.
__________ represent a pair of shared electrons
unshared electron pair
An ____________________________ is a pair of valence electrons that is not shared between atoms. It is a lone nonbonding pair. The __________________________ must be represented by dots.
Sometimes atoms share _______ than one pair of valence electrons. Atoms from double or triple covalent bonds if they can attain a noble gas electron configuration. A double bond is when atoms share two pairs of electrons (4 total). A triple bond is when atoms share three pairs of electrons (6 total).
number of bonds
_______________________ = (wants - has)/2
coordinate covalent bond
When one atom donates both bonding electrons in a covalent bond, the bond is called a _______________________________. In this type of bond, the shared electron pair comes from one of the bonding atoms.
An __________ represents a pair of electrons that is donated in a coordinate covalent bond.
a tightly bound group of atoms that has a positive or negative charge and behaves as a unit, most polyatomic cations and anions contain covalent and coordinate covalent bonds, they usually have a charge because the collection of atoms has either gained an extra electron or else it has lost an electron, a charged group of covalently bonded, made up of more than one atom, they bond with other elements as a unit (treat it as just a very large ion)
____________ shows a selected list of polyatomic ions.
Ionic compounds containing polyatomic ions include ______ ionic and covalent bonding.
When a chemical compound has at least ____ or more atoms of different elements, then 1 group of those atoms will be a polyatomic ion. Thus, look at Table E to identify the polyatomic ion.
When drawing a polyatomic ion, draw ________ around the electron dot diagram and indicate the charge.
The _____________ of a polyatomic ion shows the number of electrons in addition to valence electrons present. _____________________ polyatomic on is a part of an ionic compound.
Data about the bonding distance and bond strength are between possible drawing configurations and really indicate a ____________________.
Certain molecules and ions are best described by writing two or more Lewis structures; the real molecule or ion is a ________________________ of these structures. Neither is correct, it is actually a hybrid of the two.
The _____________________ is used to represent a resonance hybrid. The possible alternatives are drawn with arrows between them. No back and forth changes occur, but a double headed arrow is used,
___________ or Valence Shell Electron Pair Repulsion predicts the three dimensional shape of molecules. The name tells you the outside electrons (valence shell) and the electron pairs try to get as far away as possible from each other (electron pair repulsion). This helps determine the angles of bonds. According to this theory, the repulsion between electron pairs causes molecular shapes to adjust so that the valence electron pairs stay as far apart as possible. They are based on the number of pairs of valence electrons both bonded and unbonded.
Unshared pairs of electrons have no bonding atom vying for them, thus the nucleus of the atom that the pair comes from holds onto them closer. This strongly repels the bonding pairs pushing the bonds closer together,
greater repulsive forces
Nonbonding electron pairs exert _____________________________ on adjacent electron pairs and thus tend to compress the angles between the bonding pairs.
Carbon dioxide, HCl, mutual repulsion of 2 electron clouds forces the clouds to opposite sides of the shape creating a ______________ shape, symmetrical shape, bold angle is 180 degrees
CH4, four electron pairs are farthest apart, no unshared pars of electrons, farthest the elctron pairs can be from each other are 109.5 degrees, symmetrical shape, same for all molecules with 4 pairs of bonded electrons
bent or angular
water, 2 bonding pairs and 2 unshared pairs of electrons, 2 unshared pairs repel the bonding pairs, asymmetrical, bond angle is 105 degrees
pyramidal or trigonal pyramidal
NH3, NF3, 3 bonding pairs of electrons and 1 unshared pair of electrons, the unshared pair of electrons pushes bonding electrons closer together, asymmetrical shape, bond angles are 107 degrees
exception to the octet rule, acquires less than a complete octet (BF3, _______ only needs 6 valence electrons)
Phosphorous and Sulfur
expand the octet to include 10 or 12 electrons (PCl5, SF6)
trigonal planar shape
BF3, BH3, C2H4, 6 valence electrons around the central atom, 3 bonding pairs and NO unshared pairs of electrons (similar to pyramidal but NO unshared pairs), symmetrical shape, bond angle is 120 degrees
nonpolar covalent bonds
Both H2 and F2 are held together by _________________________. ______________________________ form when 2 atoms with the same electronegativity share electrons. The electrons are shared equally by the two atoms. All diatomic molecules are held together by ______________________.
When 2 different atoms bond covalently, there is an _________ sharing. The more electronegative atom will have a stronger attraction, and will acquire a slightly negative charge. The less electronegative atom has a slightly positive charge. It is called a polar covalent bond or a polar bond.
____________________ is based on partial charges of individual atoms in a molecule and on molecular shape.
Molecules held together by only nonpolar covalent bonds are always nonpolar molecules.
Due to the _______ of the molecule, sometimes molecules that are held together by polar covalent bonds are also nonpolar molecules because there is a uniform distribution of charge making the molecule nonpolar. Examples include CO2, CH4, and CCl4. These 3 have symmetrical shapes (linear or tetrahedral) resulting in a nonpolar molecule.
The effect of polar bonds on the polarity of the _________ molecule depends on the molecular shape and the orientation of the polar bonds (whether charges are symmetrical or asymmetrical at the end of the molecule). A polar bond tends to make the _________ molecule polar; one end is slightly negative while the other is slightly positive.
A molecule that has 2 poles (a polar molecule) is called a ____________.
the force of attraction between molecules in the solid or the liquid states, can be weak or strong, cause different physical properties such as melting point and solubility, they are weaker than weaker than either ionic or covalent bonds, they are what make solid, liquid and gaseous molecular compounds possible
London Dispersion Forces
weakest of all intermolecular forces, caused by movement of electron within a molecule, occurs in all molecules even between nonpolar molecules, the nucleus of one molecule (or atom) attracts the electrons of the adjacent molecule (or atom), the force increases as the number of electrons increases, increase in attraction with increasing molecular size, explains how onpolar molecules wihtout attraction for one another can exist other than just as gases, (halogens start as gases; bromine is a liquid; iodine is a solid - all in group 17)
occurs when polar molecules are attracted to each other, weak attraction, electrical attraction involved occurs between the oppositely charged regions of polar molecule, approximately 1% the the strength of a covalent bond, positive region of one molecule attracts the negative region of another molecule, slightly stronger than dispersion forces, similar to but much weaker than ionic bonds because molecules only have a slight positive or negative charge
The ______________________ attraction is appropriately named, as a polarized molecule (water) is attracted to an ion. This is how compounds, particularly ionic compounds dissolve in water. The negative ends of water dipoles surround a cation. The positive ends of water dipoles surround an anion. The attractions can be quite strong because the ions have full charges.
similar to dipole-dipole attraction, but it this type of bonding is MUCH stronger, it occurs when a hydrogen atom is covalently bonded to a highly electronegative atom and weakly bonded to an unshared electron pair of a nearby highly electronegative atom, dipole-dipole attraction in which hydrogen is bound to a highly electronegative atom (F, O, N, or Cl), these type of bonds are typically about ten times stronger than dipole-dipole attractions, the hydrogen in one molecule attracts the unbounded pair of electrons in the molecules next t it, this is the strongest of the intermolecular forces, these type of bonds are extremely important in determining the properties of water, the hydrogen is left very electron deficient, thus it shares with something nearby, hydrogen is also the ONLY element with no shielding for its nucleus when involved in a covalent bond, as atomic size increases, this type of bond gets stronger, molecules that experience hydrogen bonds have higher boiling and melting points (more energy required to separate the molecules)
Some chemicals are gases, some are liquids, and some are solids because of the type of bonding and the __________ of the intermolecular forces, in particular whether they are ionic or covalent bonds. Covalent bonds show a great range of properties because of varying intermolecular forces.
Melting point and boiling points of molecular compounds are ______ compared to ionic compounds. Covalent bonds are not as strong as ionic bonds.
Most __________ formed from molecules have only weak attractive forces holding them together. However a few solids of molecules do not melt until 1000 degrees C or decompose without melting at all. These are called network solids.
a strong on-going link of nonpolar covalent bonds (ex: diamonds, graphite, silicon, sand or quartz), they have higher melting and boiling points then even ionic compounds, they are poor conductors of heat and electricity, they are hard and strong, solids in which of the atoms are covalently bonded to each other
Some covalently bonded substances DO NOT form ___________ molecules.
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