Ch. 1: Gen Chem Electronic Structure & Bonding

Question 1

atomic number

Answer 1

of protons in its nucleus (or the number of electrons that surround the neutral atom).

Question 2

mass number

Answer 2

sum of atom’s protons and neutrons.

Question 3

isotopes

Answer 3

atoms that have the same atomic number but different mass numbers.

Question 4

atomic weight

Answer 4

average mass of the atoms in the element.

Question 5

molecular weight

Answer 5

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

Question 6

atomic orbital

Answer 6

the volume of space around the nucleus where an electron is most likely to be found. The closer the atomic orbital is to the nucleus, the lower is its energy.

Question 7

Minimum energy corresponds to _____ .

Answer 7

maximum stability

Question 8

Degenerate orbitals have the _____ energy.

Answer 8

same

Question 9

Electrons are assigned to orbitals (atomic or molecular) following the

(1) ____________________,
(2) ____________________, and
(3) ____________________ .

Answer 9

(1) Aufbau principle,
(2) Pauli exclusion principle, and
(3) Hund’s rule.

Question 10

Octet rule states _______________ in order to fill its outer shell or attain an outer shell with eight electrons.

Answer 10

that an atom will give up, accept, or share electrons

Question 11

Electronegative elements readily _____ electrons.

Answer 11

acquire

Question 12

Electronic configuration of an atom describes ___________________ .

Answer 12

the atomic orbitals occupied by the atom’s electrons

Question 13

A proton is (1) __________ charged hydrogen ion; a hydride ion is a
(2) ___________ charged hydrogen ion.

Answer 13

(1) positively

(2) negatively

Question 14

A polar covalent bond is (1) _________ .
A polar covalent bond has a
(2) __________ (a positive end and a negative end), measured by a dipole moment.

Answer 14

(1) a covalent bond between atoms with different electronegativities
(2) dipole

Question 15

formula for calculating dipole moment of a bond

Answer 15

the size of the charge X the distance between the charges

Question 16

(1) _________ are electrons in inner shells.

(2) _________ are electrons in the outermost shell.

Answer 16

(1) core electrons

(2) valence electrons

Question 17

formula for formal charge

Answer 17

of valence electrons - # of electrons the atom has to itself (all the lone-pair electrons and one-half the bonding electrons)

Question 18

Lewis structures indicate _______ .

Answer 18

which atoms are bonded together and show lone pairs and formal charges

Question 19

A (1) _________ has a positively charged carbon, a (2) _________ has a negatively charged carbon, and a (3) ______ has an unpaired electron.

Answer 19

(1) carbocation
(2) carbanion
(3) radical

Question 20

According to _____________ , covalent bonds result when atomic orbitals combine to form molecular orbitals.

Answer 20

molecular orbital (MO) theory

Question 21

Two atomic orbitals combine to give a

(1) ____________ and a higher energy
(2) ____________ .

Answer 21

(1) bonding MO

(2) antibonding MO

Question 22

What do electrons in a bonding MO do? What do electrons in an antibonding MO do?

Answer 22

Electrons in a bonding MO assist in bonding. Electrons in an antibonding MO detract from bonding.

Question 23

There is zero probability of finding an electron at a ______.

Answer 23

node

Question 24

Sigma bonds vs. pi bonds

Answer 24

Sigma bonds are cylindrically symmetrical bonds. Pi bonds are formed through side-to-side overlap of parallel p orbitals.

Question 25

Which one is stronger: a sigma bond or a pi bond?

Answer 25

A sigma bond is stronger than a pi bond.

Question 26

What does carbon have to do to form 4 bonds?

Answer 26

Carbon has to promote an electron from an s orbital to an empty p orbital.

Question 27

C, N, O, and the halogens form bonds using (1) _____ . Hybridization of C, N, or O depends on the number of pi bonds the atom forms: no pi bonds = (2) ___, one pi bond = (3) ___, and two pi bonds = (4) ___.
Exceptions are carbocations and carbon radicals, which are (5) ___ .

Answer 27

(1) hybrid orbitals
(2) sp3
(3) sp2
(4) sp
(5) sp2

Question 28

All single bonds in organic compounds are ______ bonds.

Answer 28

sigma

Question 29

A double bond consists of (1) ________; a triple bond consists of (2) _________.

Answer 29

(1) one sigma bond and one pi bond

(2) one sigma bond and two pi bonds

Question 30

The greater the electron density in the region of orbital overlap, the _________ the bond.

Answer 30

shorter and stronger

Question 31

Rank the strength of the main 3 bonds from lowest to highest.

Answer 31

single bond < double bond < triple bond

Question 32

___________ is determined by hybridization: sp3 is tetrahedral, sp2 is trigonal planar, and sp is linear.

Answer 32

Molecular geometry

Question 33

____________ around an atom stay as far apart as possible.

Answer 33

Bonding pairs and lone-pair electrons

Question 34

The ____________ in the orbital used to form a bond, the shorter and stronger the bond and the larger the bond angle.

Answer 34

more s character