2. Structure and Bonding [revised]

Question 1

explains that electrons are in 3-dimensional shaped electron clouds that represent the probability of an electron’s location.

Answer 1

QUANTUM THEORY

Question 2

explains that the electrons are in orbits or shells.

Answer 2

BOHR’S THEORY

Question 3

the idea of an electron “orbiting” the
nucleus like planets orbiting the sun.

Answer 3

orbit

Question 4

electron clouds that represent the shape of probability for an electron’s location.

Answer 4

orbitals

Question 5

tells about the detailed location of
electrons in an atom, the specific electron
orbitals that the electrons are found.

Answer 5

electron configuration

Question 6

How many orbitals are in the fourth
energy level?

Answer 6

The 4th level contains s, p, d, and f orbitals,
so the TOTAL NUMBER OF ORBITALS is 16.

Question 7

How many orbitals of each type are
there? For s, p, d, and f?

Answer 7

s – 1
p – 3
d – 5
f - 7

Question 8

__% of more than 30 million chemical compounds contain carbon.

Answer 8

90%

Question 9

Who is often credited as the father of modern atomic theory?

Answer 9

JOHN DALTON

Question 10

TRUE OR FALSE

1. Indivisibility of atom
2. All atoms of the same element are
   identical
3. Different elements have very different
   types of atoms or differ in all respects

Answer 10

1. wrong
2. wrong, isotopes
3. wrong, isobars

Question 11

Who proposed the planetary model of the
atom?

Answer 11

Niels Bohr

Question 12

TRUE OR FALSE

1. Electrons orbit the nucleus in
   orbits that have a set size and energy.
2. The energy of the orbit is related to its size.
3. Radiation is absorbed or emitted when an electron moves from one orbit to another.

Answer 12

1. wrong
2. true
3. true

Question 13

states that there is an inherent uncertainty in the act of measuring a variable of a particle

Answer 13

Heisenberg Uncertainty Principle

Question 14

model when electrons where originally thought to orbit around the nucleus in defined paths

Answer 14

electron orbit model

Question 15

model when it was discovered that electrons move in waves in a defined space called an electron cloud

Answer 15

electron cloud model

Question 16

Structure of an atom: small diameter size

Answer 16

2 x 10-10 m = 200 pm

Question 17

very dense; contains protons and neutrons

▪ protons (positively charged)
▪ neutrons (neutral)
▪ small (10-15 m)

Answer 17

nucleus

Question 18

▪ negatively charged
▪ located in space remindful of a cloud (10-10 m) around nucleus

Answer 18

electrons

Question 19

number of protons in nucleus

All atoms of same element have the same Z value

Answer 19

atomic number (Z)

Question 20

number of protons plus neutrons

Answer 20

mass number (A)

Question 21

atoms of the same element with different numbers of neutrons and thus different A.

Answer 21

isotopes

Question 22

_______ of an element is weighted average mass in atomic mass units (amu) of an element’s naturally occurring isotopes.

Answer 22

The atomic mass

Question 23

four different kinds of orbitals for electrons based on those derived for a hydrogen atom

Answer 23

s, p, d, f

Question 24

most important orbitals in organic and biological chemistry

Answer 24

s and p orbitals

Question 24

spherical, nucleus at center

Answer 24

s orbitals

Question 25

dumbbell-shaped, nucleus at middle

Answer 25

p orbitals

Question 26

elongated dumbbell-shaped, nucleus at center

Answer 26

d orbitals

Question 27

tetrahedral, nucleus at center

Answer 27

f orbitals

Question 28

____ are grouped in shells of increasing size and energy

Answer 28

orbitals

Question 29

Each orbital can be occupied by how many electrons

Answer 29

two electrons

Question 30

First shell contains one s orbital, denoted as 1s, holds only ___ electrons

Answer 30

2 electrons

Question 31

Second shell contains one s orbital (2s) and three p orbitals (2p), holds ____ electrons

Answer 31

8 electrons

Question 32

Third shell contains an s orbital (3s), three p orbitals (3p), and five d orbitals (3d), holds __ electrons

Answer 32

18

Question 33

Lobes of a p orbital are separated by region of zero electron density, which is called a _____.

Answer 33

node

Question 34

▪ lists orbitals occupied by its electrons. (i.e., lowest energy arrangement)

Answer 34

Ground-state electron configuration

Question 35

states that the lowest-energy orbitals must be filled first

Answer 35

Aufbau (“build-up”) principle

Question 36

states that only two electrons can occupy an orbital, and they must be of opposite spin to have unique wave equations

Answer 36

Pauli exclusion principle

Question 37

states that if two or more empty orbitals of equal energy are available, electrons occupy each with spins parallel until all orbitals have one electron

Answer 37

Hund's rule

Question 38

_____ bonds in salts form by electron transfers

Answer 38

ionic

Question 39

(electron dot) show valence electrons of an atom as dots

Answer 39

Lewis structures

Question 40

(line-bond structures) have a line drawn between two atoms indicating a 2 e- covalent bond.

Answer 40

Kekulé structures

Question 41

Valence electrons not used in bonding are called

Answer 41

nonbonding electrons, or lone-pair electrons

Question 42

forms when two atoms approach each other closely so that a singly occupied orbital on one atom overlaps a singly occupied orbital on the other atom

Answer 42

Covalent bond

Question 43

▪ Two models to describe covalent bonding:

Answer 43

▪ Valence bond theory ▪ Molecular orbital theory

Question 44

Electrons are paired in the overlapping orbitals and are attracted to nuclei of both atoms

Answer 44

Valence Bond Theory

Question 45

Who independently observed that carbon always has four bonds

Answer 45

Kekulé and Couper

Question 46

Who proposed that the four bonds of carbon have specific spatial directions

Answer 46

van't Hoff and Le Bel

Question 47

s orbital and three p orbitals combine to form four equivalent, unsymmetrical, tetrahedral orbitals Bond angle: 109.5°: the tetrahedral angle.

Answer 47

sp3 hybrid orbitals

Question 48

2s orbital combines with two 2p orbitals, giving 3 orbitals. This results in a double bond. ▪ 120° angles ▪ The remaining p orbital is perpendicular to the plane

Answer 48

sp2 hybrid orbitals

Question 49

where electrons are most likely to be found (specific energy and general shape) in a molecule ▪ Additive combination (bonding) MO is lower in energy ▪ Subtractive combination (antibonding) MO is higher in energy

Answer 49

molecular orbital (MO)

Question 50

The π _____ MO is from combining p orbital lobes with the same algebraic sign

Answer 50

π bonding

Question 51

The π _____ MO is from combining lobes with opposite signs

Answer 51

π antibonding

Question 52

_______ structures don’t have C-H or C-C single bonds shown. They are understood.

Answer 52

Condensed structures

Question 53

charged nucleus containing positively charged protons and neutrally charged neutrons surrounded by negatively charged electrons

Answer 53

Atom

Question 54

Electronic structure of an atom is described by

Answer 54

wave equation

Question 55

__ orbitals are spherical, __ orbitals are dumbbell-shaped

Answer 55

s orbitals p orbitals

Question 56

electron pair is shared between atoms

Answer 56

Covalent bonds

Question 57

electron sharing occurs by overlap of two atomic orbitals

Answer 57

Valence bond theory

Question 58

bonds result from combination of atomic orbitals to give molecular orbitals, which belong to the entire molecule

Answer 58

Molecular orbital (MO) theory

Question 59

Circular cross-section and are formed by head-on interaction

Answer 59

Sigma (σ)bonds

Question 60

“dumbbell” shape from sideways interaction of p orbitals

Answer 60

Pi (π) bonds

Question 61

In single bonds with tetrahedral geometry, carbon has four ____ hybrid orbitals

Answer 61

sp3 hybrid orbitals

Question 62

In double bonds with planar geometry, carbon uses three equivalent ___ hybrid orbitals and one unhybridized p orbital

Answer 62

sp2 hybrid orbitals

Question 63

Carbon uses two equivalent __ hybrid orbitals to form a triple bond with linear geometry, with two unhybridized p orbitals

Answer 63

sp hybrid orbitals

Question 64

Atoms such as nitrogen and oxygen hybridize to form strong, oriented bonds ▪ The nitrogen atom in ammonia and the oxygen atom in water are ___ hybridized

Answer 64

sp3 hybridized