exam 3

Question 1

what effect does bonding have on potential energy

Answer 1

it LOWERS potential energy between positive and negative particles

Question 2

ionic bond

Answer 2

nonmetal & metal (electron transfer)

Question 3

covelant bonding

Answer 3

nonmetal & nonmetal (electron sharing)

Question 4

metallic bonding

Answer 4

metal & metal (sea of electrons)

strongest type of bonds

Question 5

Lewis dot structures use valence electrons from the…

Answer 5

group #

Question 6

octet rule

Answer 6

when atoms bond they lose, gain or share electrons to attain a filled outer layer of 8 (H & Li are exceptions)

Question 7

ionic bonding model

Answer 7

the transfer of electrons from metal atoms to non metal atoms

(atoms want to reach the nearest noble gas)

Question 8

lattice energy

Answer 8

the enthalpy change associated with the process of separating 1 mol of ionic solid into gaseous ions

Question 9

lattice energy increases with…

Answer 9

decrease in ionic radius

increase in ionic charge

Question 10

bond order

Answer 10

the # of electron pairs being shared by a given pair of atoms

Question 11

bond energy/strength

Answer 11

energy to separate = energy to form

always positive: breaking bonds is ENDOTHERMIC

Question 12

bond length

Answer 12

the distance between the nuclei

Question 13

higher bond order results in…

Answer 13

smaller bond length &

higher bond energy

Question 14

molecular covelant substances are ______ and have _______ melting points

Answer 14

weak,low (due to weak forces between them)

Question 15

breaking bonds

Answer 15

endothermic (positive)

Question 16

forming bonds

Answer 16

exothermic (negative)

Question 17

highest lattice energy

Answer 17

highest product of charges + smallest radius

charge first/radius second

Question 18

electronegativity

Answer 18

relative ability of bonded atoms to attract shared electrons

Question 19

oxidation #

Answer 19

valence e - (# of shared e + unshared e)

shared e go to the most electronegative

Question 20

bond order

Answer 20

(# of electrons bonded - # electrons not bonded) divided by 2

Question 21

formal charge

Answer 21

= # of valence e ➖ (# of unshared valence ➕ 1/2 # shared valence e)

Question 22

formal charges must sum….

Answer 22

to the actual charge of the species

0 for a molecule / ionic charge for an ion

Question 23

picking the best resonance based on FC

Answer 23

prefer smaller formal charges, most negative FC should be on the most electronegative

Question 24

formal charge is used to….

Answer 24

examine resonance structures & determine best fit

Question 25

electron arrangement

Answer 25

bonding & non bonding groups around a central atom (can yield varied molecular shapes)

Question 26

molecular shape

Answer 26

relative position of the nuclei bonding groups ONLY

Question 27

linear

Answer 27

2 bonding groups

180° ideal bond bond angle

Question 28

lone pairs ______ the angle between bonding pairs

Answer 28

decrease

Question 29

the ______ the bond angle the weaker the repulsion

Answer 29

greater

Question 30

double bonds have more electron density and repel _________ more than they repel eachother

Answer 30

electrons in single bonds

Question 31

trigonal planar

Answer 31

3 electron groups
120° ideal bonding angle

when you have 1 lone pair
the structure is BENT

Question 32

tetrahedral arrangement

Answer 32

4 electron groups
109.5° ideal bond angle

4/0: tetrahedral
3/1: trigonal pyramidal
2/2: bent

Question 33

trigonal bypriamidal

Answer 33

5 bonding groups
3 120° & 2 90° ideal bond angles

5: trigonal bypriamidal
4/1: see-saw
3/2: T-shaped
2/3: linear

Question 34

octahedral

Answer 34

6 electron groups
90° bond angles

6: octahedral
5/1: square pyramidal
4/3: square planar

Question 35

covenant bonds are polar when…

Answer 35

the atoms have different electronegitivities

Question 36

non-polar

Answer 36

net dipole= 0
everything cancels out
equal sharing of electrons

Question 37

polar

Answer 37

net dipole >0

unequal electron sharing, asymettrical

Question 38

Born Haber Cycle

Answer 38

1. sublimation
2. dissociation
3. ionization
4. electron affinity
5. formation
6. lattice energy

Question 39

atomic radius is highest …

Answer 39

bottom left corner

Question 40

electronegativity is highest…

Answer 40

top right corner

Question 41

when oxygen is present the heat_____

Answer 41

decreases

Question 42

repulsion

Answer 42

high potential energy

Question 43

attraction

Answer 43

low potential energy

Question 44

bond length _____ when atomic radius increases

Answer 44

increases

Question 45

bond polarity and ionic character increase with a _____

Answer 45

increasing difference in electronegitivity

Question 46

electronegativity increases….

Answer 46

diagonally from bottom left to upper right

Question 47

bond strength INCREASES as atomic radius

Answer 47

DECREASES

Question 48

molecule will be non polar if:

Answer 48

the shape around the central atom has no lone pairs (unless square planar or linear)

if all atoms around the central atom are the same

Question 49

mass=

Answer 49

concentration x molar mass x volume

mol x gram/mol x liters

Question 50

mass=

Answer 50

concentration x molar mass x volume