chem ch8 test

the transfer of electrons form ______________

ionic bonds

The ____________________ occurs when atoms both need to gain valence electrons

sharing of electrons

sharing electrons is another way to gain ________________

noble gas notation

Octet rule-

atoms tend to gain, lose or share electrons to achieve a stable configuration of 8 valence elctrons

covalent bonds-

results from shared valence electrons

the shared electrons are considered to be a part of the complete outer energy level of ________________ involved

both atoms

usually occurs between elements that are ________________ on the periodic chart

close to each other

Majority of covalent bonds are formed between ____________ elements

non metallic

molecule-

formed when 2 or more atoms bond covalently

diatomic molecules-

molecules F, Cl, Br, I, N, O, and H

diatomic molecules exist this way because the two-atom molecules are more ______ then the individual ones

stable

At the point of ____________________ , the attractive forced balance the repulsive forces

maximum attraction between atoms

single covalent bonds-

when a single pair is shared

each shared pair represents a _________

bond

electrons are _____________ regardless of which atom or energy level is their source

identical

electrons in the electron cloud are not static- they are moving at almost the ________________

speed of light

electrons are attracted to the positively charged _____________

nucleus

when a covalent bond forms, __________________ contribute to the force that attracts the electrons

the nuclei of both atoms

a single atom _______________ have sole ownership of the shared electrons

does not

group 17 share one pair of electrons and ____ bond

one

group 16 share two pairs of electrons and _____ bonds

two

group 15 share three pairs of electrons and _____ bonds

three

group 14 share four pairs of electrons and ______ bonds

four

multiple covalent bonds-

double and triple bonds

sigma bond-

a single bond is formed by end to end overlap of orbits directly between the atoms

Pi bond-

a side by side parallel overlap its always the second or third bond

bond length-

depends on the size of the bonded atoms and the number of electron pairs that they share

an energy change __________ is involved in the formation or breaking of a bond

always

bond disassociation energy-

the energy needed to break a covalent bond

breaking a bond always requires the ________________

addition of energy

bond disassociation energy is a _________ value

positive

the bond length and bond disassociation energy are related: as 2 atoms are bonded _______ __together,__ ______ amounts of energy are required to separate them

closer, greater

endothermic reaction-

occurs when greater amount of energy is required to break the existing bond in the reactants than is released when the new bonds form in the production

for an endothermic reaction, energy must be _________ for the products to form

absorbed

exothermic reaction-

occurs when more energy is released forming the new bonds than is required to break the bonds in the initial reactants

for an exothermic reaction, energy must be released for the products to form

the first element in the formula is always named first, using the __________ name

entire

the second element in the formula is named using the root of the element and adding the suffix _______

ide

prefixes are used to indicate the _______________ of each type that are present in the compound

number of atoms

one exception to using the prefixes is that the first element in the formula __________ uses the prefix mono

never

binary acids-

contains H and one other element

use the prefix _________ to indicate the H part

hydro

the second part uses the root of the second element and adds the suffix ____ and the word acid

\-ic

5 different representations of molecules;

molecular formula, structural formula, space-filling molecular model, Lewis structure, and ball-and-stick model

the overlap of the orbitals that share electrons determines the molecular _________ of a molecule

shape

the shape of a molecule determines many of its ________________ prop

physical and chemical

Lewis structure-

used to show the distribution of shared and lone pairs of electrons in a molecule

predict the __________ of certain atoms

location

H is always ______________ because it can only share one pair of electrons

terminal

the atom with the least attraction to the shared electrons is the _____________ (usually closer to the left of the periodic table)

central atom

central atom located in center of molecule and other atoms become __________ atoms

terminal

determine the _________________ available for bonding; the number of valence electrons in the atoms of the molecule

total number of electrons

divide the number of electrons by two to determine the number of _______________

bonding pairs

place one bonding pair between the _________ each of the terminal atoms

central atoms

determine the number of remaining pairs by _________ the number of electron pairs aready used

subtracting

place the lone pairs around each terminal atom to satisfy the ______________

octet rule

any remaining pairs are assigned to the ____________

central atom

of a _____________ is not surrounded by 4 electron pairs, you must convert one or two of the lone pairs on a terminal atom to a double or triple bond between the central and terminal atoms

central atom

polyatomic ion:

a group of atoms that are covalently bonded that possess an overall charge

a polyatomic ion with a ____________ has gained electrons equal to the charge

negative

resonance:

occurs when more than one valid Lewis structure that can be written for a molecule or an ion

resonance structures _____ in the position of electron pairs, never in the position of the atoms

only

the shape of a molecule determines its ____________________

ability to react with other molecules

hybridization-

a process in which atomic orbitals mix to form new identical hybrid orbitals

VSEPR model is used to determine the ____________

molecular shape

VSEPR stands for….

Valence Shell Electron Pair Repulsion Model

based on an arrangement of atoms that will _________ the repulsion of shared and unshared pairs of electrons around a central atom

minimize

electrons in a molecule are located as _____________ as they can be because of electron repulsion

far apart

lone pairs also occupy a position in space but a lone pair takes up a _______________ amount of space than the shared pairs because the unshared pairs generate a greater repulsion than shared pairs do

greater

electron affinity-

a measure of the tendency of an atom to accept an electron

electron affinity increases ________ the period

across

electron affinity _________ down the periodic char

decreases

noble gases are not listed because they generally do not form ____________

compounds

electronegativity-

ability of an atom to attract electrons in a chemical bond

the easier it is for an atom to accept an electron, the _________ its electronegativity

higher

covalent bonds-

formed from sharing electron pairs

nonpolar covalent bonds-

equal sharing of electron pair between atoms

polar covalent bonds-

unequal sharing of electron pair

form when the atoms pull on electrons in a molecue _____________

unequally

electrons spend more time around that atom than they do around another resulting in _____________ at the ends of the bond called a dipole

partial charge

bonding is often not clearly ionic or ________________

covalent

_____________ between electronegativity values used to determine type of covalent bond being formed

difference

as the electronegativity difference _______________ the bond becomes more ionic in character

increases

>1.7

mostly ionic

0\.4-1.7

polar covalent

mostly covalent

0\.0

non polar covalent

non-polar molecules are not attracted by an __________ field. polar molecules align with an electric field

electric

molecular shape can also determine ______________

polarity

molecules are either polar or nonpolar depending on the _____________________________________________ they contain

location and nature of the covalent bonds

in some cases the charge distribution is not equal and therefore the molecule is ______________

polar

Solubulity

the property of a substance’s ability to dissolve in another substance

polar molecules and ionic substances are usually _____________ in polar substances

soluble

non-polar molecules dissolve only in _______________ substances

non-polar

covalent bonds between atoms are strong, but the attraction forces between molecules are _______

weak

dipole-dipole forces-

the force between two oppositely charged ends of two polar molecules

a _______________ is an especially strong dipole- dipole force between the hydrogen end of one dipole and a fluorine, oxygen, or nitrogen atom on another dipole

hydrogen

molecular solids tend to be _____ and have low melting points

soft

covalent network solids-

result when each atom is covalently bonded to many other atoms in the solid

diamonds are hard and have _______ melting points

high