Ch.1

Question 1

Isotope

Answer 1

same atomic number but different mass number

Question 2

Molecular mass

Answer 2

the sum of the atomic masses of all the atoms in the molecule

Question 3

Degenerate orbital

Answer 3

orbitals that have the same energy p(x), p(y)

Question 4

3 rules that specify which atomic orbitals an atom’s electrons occupy

Answer 4

1) aufbau principle [ an electron always goes into the available orbital with the lowest energy]
2) The Pauli exclusion principle[ no more than two electrons can occupy each atomic orbital, and the two electrons must be of opposite spin
3) Hund’s rule [ when there are two or more atomic orbitals with the same energy, an electron will occupy an empty orbital before it will pair up with another electron]

Question 5

Valence electron

Answer 5

electrons in an atom’s outermost shell

Question 6

core electron

Answer 6

electrons in inner shell

Question 7

nonpolar covalent bond

Answer 7

electronegativity difference between the bonded atoms is less than 0.5

Question 8

polar covalent bond

Answer 8

electronegativity difference between the bonded atom is between 0.5 and about 1.9

Question 9

ions are held by?

Answer 9

electrostatic attraction[ an attractive force between opposite charges]

Question 10

dipole moment of a bond

Answer 10

size of the charge * the distance between the charges [ 1 Debye = 1.0 * 10^-18]

Question 11

Electrostatic potential map

Answer 11

Red- most negative, Blue= most positive

Question 12

formal charge

Answer 12

the number of valence electrons[ not bonded to other atoms] - (the number of lone pair electrons + the number of bonds)

Question 13

Constitutional isomer

Answer 13

molecules that have the same atoms but differ in the way the atoms are connected

Question 14

Kekule structure

Answer 14

similar to Lewis structures except that lone pairs are normally omitted

Question 15

condensed structures

Answer 15

omit some( or all) of the covalent bonds and list atoms bonded to a particular carbon( or N/ O ) next to it

Question 16

Skeletal Structures

Answer 16

atoms other than carbons are shown, and hydrogens bonded to atoms other than carbon are also shown

Question 17

Heisenberg uncertainty principle

Answer 17

precise location and the exact momentum of an atomic particle cannot be simultaneously determined

Question 18

Node

Answer 18

region where the probability of finding an electron falls to zero

Question 19

sigma bond

Answer 19

formed when the two s orbital overlap

Question 20

bond dissociation energy

Answer 20

energy required to break a bond or the energy released when a bond is formed

Question 21

_________ properties of the electron that cause two atomic orbitals to form two molecular orbitals

Answer 21

wave-like

Question 22

pi bond

Answer 22

side- to side overlap of two parallel p orbitals

Question 23

pi bonding Mo has ____ node(a nodal plane that passes through both nuclei), pi*(anti-bonding) bonding Mo has ____ nodal plane

Answer 23

1, 2

Question 24

VSEPR model ( inadequate for some molecules because)?

Answer 24

Valence-shell-electron-pair repulsion model

/ it does not allow for antibonding molecular orbitals

Question 25

All single bonds in organic compounds are ____

Answer 25

sigma bond