m17 | m18

Question 1

What do you call the structures that show:
- which atoms in a molecule are bonded to each other
- the number of electrons shared in each bond?

Answer 1

Lewis structures

Question 2

Enumerate step-by-step.

What are the four basic steps in drawing a Lewis structure?

Answer 2

1. Determine the connectivity of the atoms in the molecule
2. Determine the total number of valence electrons
3. Add the valence electrons to the molecule
4. Attempt to fill each atom’s octet

Question 3

Plus, determine which step is being explained given the description.

In general, the (?) atom in the molecule is the (?) electronegative element.

Answer 3

Step 1
central atom; least electronegative

Question 4

Plus, determine which step is being explained given the description.

If the molecule is negatively charged (add/subtract) one electron, and if positively charged (add/subtract) electron.

Answer 4

Step 2
negatively charged = add
positively charged = subtract

Question 5

Hydrogen atoms and halide atoms are almost always peripheral atoms (non-central atoms) because these atoms…

Answer 5

usually form only one bond

Question 6

Plus, determine which step is being explained given the description.

Start adding the electrons by making a bond between the central atom and each peripheral atom; subtract (one/two/three) valence electrons from the total v.e.

Answer 6

Step 3
subtract two electrons
(electron pair)

Question 7

Which do you make sure to fill in first, provided that the octet rule is followed? The peripheral atoms or the central atoms?

Answer 7

1. central atoms
2. peripheral atoms

Question 8

Where do you assign the left over electrons once all peripheral atoms have their octets filled already?

Answer 8

the central atom

Question 9

Plus, determine which step is being explained given the description.

You can’t break the octet rule for (fourth/second/first) row atoms, meaning the sum of bonds + lone pairs can’t exceed (8/2/4).

Answer 9

Step 4
second row atoms; 4

Question 10

Enumerate.

What are the three bond types in chemistry?

Answer 10

• purely covalent
• polar covalent
• ionic

Question 11

Identify which bond type is being described.

• the electrons aren’t shared
• the more electronegative atom grabs a pair of electrons for itself

Answer 11

ionic bond

Question 12

Identify which bond type is being described.

• the bonding electrons are shared equally between the two atoms

Answer 12

purely covalent bond

Question 13

Identify which bond type is being described.

• electrons are shared unequally between two bonding atoms
• electrons spend more time around the more electronegative atom

Answer 13

polar covalent bond

Question 14

Identify which bond type is being described.

• the bond in this type is considered to be an attraction of opposite charges

Answer 14

ionic bond

Question 15

If the electronegativity difference between the two atoms is 0.0, the bond is…

Answer 15

purely covalent

Question 16

If the electronegativity difference is greater than 2.0, then bond is considered…

Answer 16

ionic

Question 17

If the electronegativty difference is between 0.0 and 2.0, the bond is considered…

Answer 17

polar covalent

Question 18

What do you call the quantitative scale of acidity?

Answer 18

pKa scale
^ pKa: weaker acid
v pKa: stronger acid

Question 19

What does the pKa scale help predict?

Answer 19

The direction of an acid-base reaction at equilibrium.

Question 20

Enumerate.

What are the two types of definitions when it comes to acids and bases?

Answer 20

• Brønsted–Lowry acid-base
• Lewis acid-base

Question 21

In Brønsted–Lowry acids–bases…

The Brønsted (acid/base) is a molecule or ion that donates a proton

Answer 21

Brønsted acid

Question 22

In Brønsted–Lowry acids–bases…

The Brønsted (acid/base) is a molecule or ion that accepts a proton

Answer 22

Brønsted base

Question 23

Recite the Brønsted-Lowry acid-base analogy.

Answer 23

Brønsted-Lowry = positive people (H+)
A = feed postivity |
B = eat postivity

Question 24

What is the given organic-speak for how a reaction occurs?

Answer 24

mechanism of a reaction

Question 25

A Lewis (acid/base) is a molecule or ion that accepts a pair of electrons to make a new covalent bond.

Answer 25

Lewis acid

Question 26

A Lewis (acid/base) is a molecule or ion that donates a pair of electrons to make a new covalent bond.

Answer 26

Lewis base

Question 27

Recite the analogy for Lewis acids and bases.

Answer 27

Lewis = pessimist (e-/electrons)
A = eats up electron pairs |
B = feeds electron pairs

Question 28

In drawing the schematic reaction between a Brønsted-Lowry acid and base, where should the arrow start and push towards?

Answer 28

• start: from the electron donor (Lewis Base/Brønsted Base)
• push: towards the electron acceptor (Lewis Acid / Brønsted Acid)

Question 29

What becomes of the first lone pair of electrons pushed from the electron donor?

Answer 29

It usually becomes the bonding electrons in the base-H bond.

Question 30

What is a common mistake done when drawing reaction mechanisms between acids and bases?

Answer 30

Drawing an arrow originating from an H+

H+ has no electrons

Question 31

Identify which organic -speak is being described.

deprotonated acid

Answer 31

conjugate base

Question 32

Idnetify which organic-speak is being described.

protonated base

Answer 32

conjugate acid

Question 33

What type of bond is formed whenever electrons are somewhat shared in the mechanism reaction of Lewis acids and bases?

Answer 33

covalent bond

Question 34

True or false: Brønsted acids and bases are also Lewis acids and bases respectively.

Answer 34

True

Question 36

Which type of definition do chemists prefer when it comes to the concept of acid-base reactions?

Answer 36

proton diet > electron diet
They prefer the Brønsted-Lowry definition because it’s much easier to think of most acid-base reactions in terms of proton transfers rather than in terms of electron transfers.