Covalent Bonds

Question 1

the number of shared electron pairs between two atoms is called…

Answer 1

bond order

Question 2

3 features that characterize a covalent bond:

Answer 2

• bond length
• bond energy
• polarity

Question 3

bond length

Answer 3

• avg distance between the two nuclei of atoms in a bond
• as the # of shared electron pairs increase, the two atoms are pulled closer together resulting in a decrease in bond length

Question 4

bond energy

Answer 4

• the energy required to break a bond by separating its components into their isolated, gaseous atomic states
• the greater the number of pairs of electrons shared between the atomic nuclei, the more energy is required to break the bonds holding the atoms together

Question 5

which bond has the greatest bond energy/stronger bond

Answer 5

triple bond

Question 6

which bond has the lowest bond energy/weakest bond

Answer 6

single bond

Question 7

polarity

Answer 7

-occurs when two atoms have a relative difference in electronegativities

Question 8

atom with the highest electronegativity, get the …

Answer 8

larger share of the electron density

Question 9

polar bond creates a

Answer 9

dipole

Question 10

nonpolar covalent bond

Answer 10

no separation of charge across the bond

Question 11

polar covalent bonds

Answer 11

atoms that differ moderately in their electronegativites and will share electrons unevenly
- more electronegative elements take on a partial negative charge and less electronegative elements takes on a partial positive charge

Question 12

dipole moment

Answer 12

vector quantity by the equation:
p=qd
p: dipole moment
q: the magnitude of the charge
d: the displacement vector separating the two partial charges

Question 13

coordinate covalent bond

Answer 13

• both of the shared electrons originated not he same atoms
• the lone pair of one atom attacked another atoms with an unhybridized p - orbital to form a bond
• usually found in lewis acid-base reactions

Question 14

lewis acid

Answer 14

any compound that will ACCEPT a lone pair

Question 15

lewis base

Answer 15

any compound that will DONATE a pair of electrons to form a covalent bond

Question 16

bonding electrons

Answer 16

electrons in the covalent bond that are in the valence shell

Question 17

nonbonding electrons

Answer 17

electrons in the valence shell that are not involved in covalent bonds

Question 18

resonance structures

Answer 18

represents all of the possible configurations of electrons - stable and unstable - that contribute to the overall structure

Question 19

Valence shell pair repulsion (VSEPR) theory

Answer 19

• predict the 3 dimensional molecular geometry of covalently bonded molecules.
• in this theory, electrons - whether bonding or nonbonding - arrange themselves to be as far apart as possible from each other in 3 dimensional space, leading to characterize geometries

Question 20

Nonbonding electrons exert (more/less) repulsion than bonding electrons because they reside closer to the nucleus

Answer 20

MORE

Question 21

Electronic geometry

Answer 21

the position of all electrons in a molecule where bonding or nonbonding.

Question 22

molecular geometry

Answer 22

the position of only the bonding pairs of electrons in a molecule

Question 23

polarity of molecules

Answer 23

dependent on the dipole moment of each bond and the sum of the dipole moments in a molecular structure

Question 24

all polar molecules contain

Answer 24

polar bonds

Question 25

nonpolar molecules may contain

Answer 25

non polar bonds, or polar bonds with dipole moments that cancel each other

Question 26

sigma and pi bonds describe

Answer 26

the patterns of overlap observed when molecular bonds are formed

Question 27

sigma bonds

Answer 27

result of head to head overlap

Question 28

pi bonds

Answer 28

result of the overlap of two parallel electron cloud densities