Chapter 8

Question 1

ionic bond

Answer 1

• a chemical bond that results from the electrostatic attraction between a cation and an anion
  
  • two atoms linked by a chemical bond tend to be lower in chemical energy than those two atoms w/o a bond
    
    • aka bond = less chemical energy
    • so, bonded atoms are more stable

Question 2

bond length

Answer 2

• the distance between the nuclear centers of two atoms joined in a bond
  
  • aka the distance between the atoms when E_el is at a minimum
    
    • E_el of H₂: the energy released when two moles of H atoms bond to form one mole of H₂ molecules
    • this is also the amount of energy that must be added to break this bond

Question 3

metallic bonds

Answer 3

• a chemical bond consisting of metal nuclei surrounded by a “sea” of shared electrons
  
  • the positive nucleus of each atom in a metallic solid is attracted to the electrons of the atoms that surround it which results in the formation of metallic bonds
    
    • ​unlike covalent bonds b/c they are not a pair of e- shared by two atoms
      
      • instead, the e- shared are delocalized
        
        • ​e- that are shared among more than two atoms(move freely among all the atoms in a metallic solid)
        • this is why metals are good conductors of heat and electricity

Question 4

bonding capacity

Answer 4

• the number of covalent bonds an atom forms to have an octet of e- in its valence shell
  
  • the number of unpaired dots in a Lewis structure indicates the typical bonding capacity of the atom

Question 5

bonding pair

Answer 5

a pair of e- shared between two atoms

Question 6

ione pair

Answer 6

a pair of e- that is not shared

Question 7

aldehyde

Answer 7

• an organic compound havign a carbonyl group with a single bond to a hydrogen atom and a single bond to another atom or group of atoms designated as R- in the general formula RCHO.
  
  • be able to recognize!

Question 8

carbonyl group

Answer 8

a carbon atom with a double bond to an oxygen atom

Question 9

polar covalent bond

Answer 9

• a bond characterized by unequal sharing of bonding pairs of e- between atoms

Question 10

bond polarity

Answer 10

• a measure of the extent to which bonding e- are unequally shared due to differences in electronegativity of the bonded atoms
  
  • use delta δ with + or - to indicate partial electrical charges(or use plus sign arrow)
    
    • aka - indicates more EN element

Question 11

nonpolar covalent bond

Answer 11

• a bond characterized by an even distribution of charge
  
  • e- in the bonds are shared equally by the two atoms

Question 12

electronegativity

Answer 12

• a relative measure of the ability of an atom to attract e- in a bond to itself

Question 13

ionic character

Answer 13

• an estimate of the magnitude of charge separation in a covalent bond
  
  • the greater the difference in abilities of the two atoms to attract the e- they share, the more ionic bonds btwn them

Question 14

allotropes

Answer 14

different molecular forms of the same element, such as oxygen(O₂) and ozone(O₃)

Question 15

free radical

Answer 15

an odd-electron molecule with an unpaired electron in its Lewis structure

Question 16

bond order

Answer 16

• the number of bonds between two atoms
  
  • as bond order inc, bond length decreases
    
    • triple bonds are a lot shorter than single bonds

Question 17

bond energy/bond strength

Answer 17

• the energy needed to break 1 mole of a particular covalent bond in a molecule or in a polyatomic ion in the gas phase
• usually expressed as deltaH
• all these values are positive because bond breaking is always endothermic
  
  • DH_rxn = ∑DH_{bonds breaking} - ∑DH_{bonds forming}