lecture 6 - basic fundamentals of chemistry

Question 1

what are the 2 features of a 1s orbital

Answer 1

spherical shape and holds two electrons of opposite spin

Question 2

what are the 3 features of a 2s orbital

Answer 2

spherical in shape, larger than 1s and have a node

Question 3

what are the two features on a 2p orbital

Answer 3

dumbbell in shape and have 3 different arrangements

Question 4

what are the 3 rules regarding assigning electrons to orbitals

Answer 4

1. Lower energy orbitals filled before higher energy orbitals
2. Pauli Exclusion Principle - orbital can hold two electrons of opposite spin
3. Hund’s rule - e.g. 3 electrons of one spin will fill one half of all 3 orbitals and then the other 3 electrons will fill the other half, of the opposite spin

Question 5

what causes ionic bonding

Answer 5

the electrostatic charge interaction, created by one element losing electrons and the other gaining them, between the two oppositely charged ions

Question 6

what causes covalent bonding

Answer 6

2 non-metals sharing electrons to gain a full outer shell and be stable

Question 7

are non-polar covalent bonds considered to have symmetrical or unsymmetrical electron distribution and why?

Answer 7

symmetrical - electrons are shared equally e.g. Carbon-Carbon bonds

Question 8

are polar covalent bonds considered to have symmetrical or unsymmetrical electron distribution and why?

Answer 8

unsymmetrical - electrons are not shared equally due to permanent dipoles created by different electronegativities

Question 9

what is the definition of electronegativity

Answer 9

a measure of the tendency of an atom to attract a bonding pair of electrons

Question 10

discuss electronegativity regarding metals and non-metals

Answer 10

metals have low electronegativity in order to lose electrons, whereas group 7 have very high electronegativities to gain electrons

Question 11

in regards to electronegativities, when do non-polar covalent bonds form

Answer 11

when two atoms have similar or the same electronegativity

Question 12

in regards to electronegativity, when do polar covalent bonds form

Answer 12

when two atoms electronegativities differ by 0.3-2.0 arbitrary units

Question 13

in regards to electronegativity, when do ionic bonds form

Answer 13

when the difference in electronegativity between two atoms is greater than 2.0 arbitrary units

Question 14

what do functional groups determine

Answer 14

the reactivity of a molecule

Question 15

what changes can occur when different functional groups are added to a molecule

Answer 15

polarity, the addition/deletion of double bonds, addition/deletion of lone pairs

Question 16

what functional group has the highest priority

Answer 16

carboxylic acid

Question 17

what is the order of priority of functional groups

Answer 17

carboxylic acid
carbonyl
hydroxy
alkynes
alkenes
alkanes

Question 18

what are terminal and internal alkenes determined by

Answer 18

the positions of the double bond

Question 19

Z isomers are?

Answer 19

cis - same side

Question 20

E isomers are?

Answer 20

trans isomer - opposite

Question 21

what determines a molecule to be an alkyne

Answer 21

a carbon-carbon triple bond

Question 22

how do benzene rings work

Answer 22

the double bonds have pi electrons which can move between the bonds, creating resonance structures

Question 23

what are the 3 types of Di-substituted benzenes and when do they occur

Answer 23

1,2 - Ortho benzene
1,3 - Meta benzene
1,4 - Para benzene

Question 24

what is the difference between a primary, secondary and tertiary alcohol/amine

Answer 24

primary - 1 R group
secondary - 2 R groups
tertiary - 3 R groups

Question 25

what do we use to show how many hydrogens have been replaced on an amine

Answer 25

an N for each hydrogen

Question 26

what does an amide contain that an amine doesn’t

Answer 26

a double bonded oxygen on the same carbon as the nitrogen

Question 27

what do all esters contain

Answer 27

O=C-O