Chemistry Chptr 5-6 Test

Front 1

Octet Rule

Back 1

A concept of chemical bonding that is based on the assumption that atoms tend to have either empty valence or full valence shells of 8 electrons

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covalent bond

Back 2

neutral atoms combine to share electrons

Front 3

molecular orbital

Back 3

the space where shared electrons move; it is made when 2 atomic orbitals overlap

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ion

Back 4

atom or molecule that has gained or lost electrons

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bond length

Back 5

the distance between 2 bonded atoms at their minimum potential energy; the average distance between the nuclei of 2 bonded atoms

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bond energy

Back 6

the energy required to break the bonds between 2 atoms (1 molecule of a chemical compound)

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cation

Back 7

ion with a positive charge (loss of electrons)

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nonpolar covalent bond

Back 8

a covalent bond in which the bonding electrons in the molecular orbital are shared equally

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polar covalent bond

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a covalent bond in which a shared pair of electrons is held more closely by one of the atoms (higher electronegativity)

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anion

Back 10

ion with negative charge (gain of electrons)

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dipole

Back 11

a molecule or part of a molecule that has partial positive charge and partial negative charge

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valence electron

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an electron that is found in the outermost shell of an atom and that determines the atom's chemical properties; electrons in S and P orbitals of highest level

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salt

Back 13

an ionic compound that forms when a metal atom or a positive radical replaces the hydrogen of an acid

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lewis structure

Back 14

a structural formula in which electrons are represented by dots; dot pairs or dashes between 2 atomic symbols represent pairs in covalent bonds

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unshared pair

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a nonbonding pair of electrons in the valence shell of an atom; also called lone pair

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lattice energy

Back 16

the energy released when ionic bonds are formed (the energy associated with constructing a crystal lattice relative to the energy of all constituent atoms separated by infinite distances)

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single bond

Back 17

a covalent bond in which 2 atoms share one pair of electrons

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double bond

Back 18

a covalent bond in which two atoms share two pairs of electrons

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crystal lattice

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the regular pattern in which a crystal is arranged

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unit cell

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the smallest repeating unit in a crystal lattice (the smallest portion of a crystal lattice that shows the three-dimensional pattern of the entire lattice)

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triple bond

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a covalent bond in which two atoms share three pairs of electrons

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resonance structure

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when a molecule has 2 or more possible Lewis structures (any on of 2 or more possible configurations of the same compound that have identical geometry but different arrangements of electrons)

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VSEPR theory

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valence shell electron pair repulstion: a theory that predicts some molecular shapes based on the idea that pairs of valence electrons surrounding an atom repel each other

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polyatomic ion

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a charged group of two or more bounded atoms that can be considered a single ion

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determine bond type given electronegativity values

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to determine bond type (polar covalent, non-polar covalent, or ionic) the difference of electronegativity must be determined

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conditions for an ionic compound to conduct electricity

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the substance must contain charged particles and the particles must be free to move

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why do ionic compounds have such high melting and boiling points whereas covalent compounds have lower melting and boiling points?

Back 27

since ionic bonds are stronger it takes more energy to take them apart which causes a higher melting and boiling point.

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what is the difference between the melting and boiling points for covalent compounds in comparison to ionic compounds and why?

Back 28

Covalent compounds have weaker bonds so they take up less energy and have lower melting and boiling points. Ionic bonds on the other hand have stronger bonds that take up more energy and cause higher melting/boiling points.

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Explain how a molecule that contains more than one polar bond could be considered a non polar molecule

Back 29

if the forces cancel because they are polar and depending on the shape it could also be considered a non polar molecule

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Ion electron configurations

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if it has a positive charge then subtract electrons and if it is a negative charge then add the electrons

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how are parent atoms different from their ions?

Back 31

their chemical properties change because of their different valence electron configurations

Front 32

what does a Roman numeral after the name of a cation indicate? why is it necessary for naming?

Back 32

it indicates the charge of the transition metal. without knowing the charge you can't write the correct formula because you need to balance out the charges (criss crossing)