Intro to Organic Chemistry

Question 1

what is atomic valence?

Answer 1

atomic valence is the most fundamental level of understanding overall structure of organic molecules.

Question 2

atomic valence is aka…

Answer 2

valence

Question 3

The valence of an atom is _________________________________________.

Answer 3

The number of bonds an atom will form to fill its valence (outermost) electron shell.

Question 4

Why are we interested in the valence (outermost) shell of an atom?

Answer 4

The atom achieves stability from a full valence shell, as there is no more desire for the atom to have bonds. For organic molecules, we need to know how many bonds that element will form.

Question 5

What are main group elements?

Answer 5

The elements most organic molecules are composed of.

Question 6

Describe the rule that main group elements follow:

Answer 6

Octet rule states that the main group elements have a full valence shell when there are 8 electrons in the valence shell.

Question 7

Which element is the smallest but prominent in most organic molecules?

Answer 7

Hydrogen

Question 8

Describe the rule that hydrogen follows:

Answer 8

Duet rule states that an element has a full valence shell when there are 2 electrons in the valence shell.

Question 9

What is the Lewis Dot Diagram?

Answer 9

A short hand notation to figure out the valence; a pictorial representation of the valence.

Question 10

What are the steps in generating an LDD for a main group element? Hint: there are 5.

Answer 10

1. determine the group # of element
2. group # indicates # of valence electrons possessed by the atom in valence shell
3. write the atomic symbol for the element and imagine it is contained in a 4 sided box
4. place dots (representing electron) around the symbol. Use only 4 sides of the box
5. place electrons singly at first (one per side)
6. Once each side has a single electron, continue by pairing electrons until the total

Question 11

The transferring of electrons forms what?

Answer 11

ions

Question 12

what are ions?

Answer 12

chemical species with a non-zero electrical charge, meaning they have a positive or negative charge.

Question 13

unpaired electrons are ________

Answer 13

bonds in an organic molecule

Question 14

lone pairs are ______-

Answer 14

non bonding electrons in an organic molecule

Question 15

why would an element like Neon not bond with other elements?

Answer 15

Neon is a noble gas, and noble gases already have a full valence shell ( 8 electrons, as it is in group 8). Thus, it has no desire to make any bonds to fulfill its shell. It’s stable.

Question 16

When an electron is given away, the species giving something away becomes ________ charged

Answer 16

positively; (cation)

Question 17

When a species accepts an electron, it becomes ____________ charged

Answer 17

negatively;(anion)

Question 18

The nature of an ionic bond is an electrostatic interaction, meaning ____________________

Answer 18

oppositely charged particles attract one another (e.g., Na+ and Cl-)

Question 19

when does an ionic bond form?

Answer 19

ionic bonds form when 1 atom transfers 1 or more of its valence electrons to another atom

Question 20

when does a covalent bond form?

Answer 20

covalent bonds form when there is a sharing of electrons between atoms

Question 21

Do covalent bonds form ions? why or why not?

Answer 21

No, they don’t form ions because there isn’t a transfer of electrons between atoms in order to produce them.

Question 22

a single line is the equivalent of how many electrons?

Answer 22

2 electrons

Question 23

what is a purely covalent bond?

Answer 23

a covalent bond that forms between atoms bonding with itself.

(H-H, C-C)

Question 24

When does a polar covalent bond occur?

Answer 24

covalent bonding that occurs between two different elements but not enough of a difference that the bond becomes ionic.

The sharing of electrons is unequal.

Question 25

In polar covalent bonds, what does the unequal sharing of electrons result in?

Answer 25

atoms that carry a partial electrical charge (shown by delta symbol).

Question 26

What is another name for a polar covalent bond?

Answer 26

polarized bond

Question 27

what does it mean for an atom to be less electronegative or more electronegative?

Answer 27

less electronegative: less desire for electrons (e.g., hydrogen) more electronegative: more desire for electrons (e.g., chlorine) chloride's electronegativity value = 3 , while hydrogen's electronegativity value = 2.1 (according to pauling scale). Thus, chloride is more electronegative.

Question 28

which bond has a higher melting point? ionic or covalent?

Answer 28

ionic ( >800-1000 degrees C), while covalent is under 300 degrees C (300+ would decompose)

Question 29

what is the physical state of ionic bonds?

Answer 29

brittle crystalline solids

Question 30

what is the physical state of covalent bonds?

Answer 30

solids, liquids, gases

Question 31

What is the solubility of ionic bonds?

Answer 31

dissolve readily in polar solvents, especially water.

Question 32

What is the solubility of covalent bonds?

Answer 32

range of solubilities depending on overall polarity, many are water-insoluble.

Question 33

What is the conductivity of ionic bonds?

Answer 33

aqueous solutions conduct electricity

Question 34

What is the conductivity of covalent bonds?

Answer 34

aqueous solutions don't conduct electricity.

Question 35

methane is found as a gas in its natural state and is completely _________ in water.

Answer 35

insoluble

Question 36

the preference for carbon's preference to form covalent bonds with other carbon atoms is called?

Answer 36

catenation

Question 37

why is catenation important?

Answer 37

because of carbon's preference to bond with other carbon atoms, organic molecules can consist of multiple carbon atoms covalently bonded to one another in different patterns.

Question 38

what different patterns are created in result of catenation?

Answer 38

linear chains, branched chains, rings, or any combination of these.

Question 39

Some very large organic molecules can contain hundreds of carbon atoms covalently bonded together to form the _____________ of the molecule.

Answer 39

backbone or skeleton.

Question 40

define bond order:

Answer 40

the number of bonds between a pair of atoms in a molecule.

Question 41

what is increasing bond order?

Answer 41

a molecule consisting of two carbons demonstrates increasing bond order by forming a single, double, and triple bond between the two carbon atoms

Question 42

can bond orders happen between hydrogen and carbon as well?

Answer 42

yes. the bond order is one (single bonds are present in molecules like methane and ethane)

Question 43

C-C multiple bonds have fewer hydrogen atoms. This is known as ____________ in an organic molecule.

Answer 43

unsaturation

Question 44

Unsaturated compounds are molecules that possess ______________ as a part of their structure. Since the carbons are making more than one bond to another carbon, there are fewer bonds that can be made with hydrogen atoms.

Answer 44

one or more double or triple bonds (or a ring)

Question 45

molecules that possess multiple bonds have different (typically greater) chemical reactivity as compared to molecules with only single bonds due to __________________________________.

Answer 45

the dense packing of electrons between atoms joined by multiple bonds.

Question 46

Two atoms that only make one bond: _______________________ They cannot participate in multiple bonding.

Answer 46

hydrogen and halogens.