structure of Organic Molecule

Question 1

what does the periodic table show

Answer 1

Number or electrons, neutrons and protons
 Mass of a mole of atoms
 Group-Available for bonding
 Period (shells)
 Name/symbol

Question 2

what does the group in the periodic table tell?

Answer 2

indicates number of electrons in ‘outer shell’
 Available for bonding

Question 3

what’s the trend of the atomic radius in the periodic table

Answer 3

atomic radius generally decreases as you move from left to right across a period (due to increasing nuclear charge) and increases as you move down a group (due to the increasing number of electron shells).

Question 4

what’s the trend for the non metabolic characteristics in the periodic table

Answer 4

As you move diagonally across the periodic table, non-metallic characteristics increase due to higher electronegativity and smaller atomic size.

Question 5

what’s the trend in the periodic table for metabolic characteristics

Answer 5

As you move diagonally across the periodic table from bottom left to top right, metabolic characteristics generally decreases due to higher electronegativity, smaller atomic size, and increased tendency to gain electrons, impacting metabolic rates and reactivity.

Question 6

what’s the trend in the periodic table for Electronegativity, electron affinity, and ionization energy

Answer 6

Electronegativity, electron affinity, and ionization energy generally increase across periods in the periodic table from left to right. This trend occurs due to a greater nuclear charge and decreasing atomic size, resulting in stronger attraction for electrons and a higher energy requirement to remove electrons.

Question 7

what doe the first ionisation tell?

Answer 7

The amount of energy required to remove an electron from a neutral atom in its gaseous phase(The lower this energy is, the more readily the atom
becomes a cation)

Question 8

what are 3 factors affecting the ionisation energy

Answer 8

1 -The charge on the nucleus
2 -The distance of the electron from the nucleus
3 -The number of electrons between the outer electrons and the nucleus

Question 9

why does The number of electrons between the outer electrons and
the nucleus affect the ionisation energy

Answer 9

 The inner electrons shells shield the outer electrons shells and
reduce the effect of the nuclear “pull” on those outer electrons.
 The shielding provided by the inner electrons means it will take
less energy to free outer electrons from their orbitals
 Ionization energy of an outer electron is reduced by the effects of
shielding.
 This lessening of the pull of the nucleus by inner electrons is
known as screening or shielding.

Question 10

Describes why the electron affinity decreases down a group of elements

Answer 10

Generally decreases down a group of elements
 Each atom is larger than the atom above it
 An added electron is further away from the atom’s
nucleus compared to its position in the smaller atom
 With a larger distance between the negatively-charged
electron and the positively-charged nucleus, the force of
attraction is relatively weaker

Question 11

Describes why the electron affinity increases when it moves from left to right across the period

Answer 11

Moving from left to right across a period
 Atoms become smaller as the forces of attraction
become stronger.
 This causes the electron to move closer to the
nucleus, thus increasing the electron affinity from left
to right across a period.

Question 12

describe what is electron affinity

Answer 12

the ability of an atom to accept an electron

Question 13

describe what is electronegativity

Answer 13

Measures an atom’s strength to attract and form bonds with
electrons

Question 14

describe why as you move to the right across a period of elements,
electronegativity increases

Answer 14

When the valence shell of an atom is less than half full, it requires
less energy to lose an electron than gain one and thus, it is easier to
lose an electron.
Conversely, when the valence shell is more than half full, it is easier
to pull an electron into the valence shell than to donate one

Question 15

explain why the electronegativity decreases down the group

Answer 15

this is because there is an increased distance between the valence
electrons and nucleus

Question 16

what is the most electronegative element ?

Answer 16

fluorine

Question 17

when are ionic bond formed?

Answer 17

onic bonds are formed when the electronegativity
difference between the atoms is > 1.7

Question 18

when are covalent bonds, formed?

Answer 18

Covalent bonds are formed when the electronegativity
difference between the atoms is < 1.7

Question 19

what does an ionic bond do?

Answer 19

transfer electron(s)

Question 20

what does a covalent bond do?

Answer 20

share electrons

Question 21

are electrons shared equally in covalent bonds?

Answer 21

Unless difference = 0, there is unequal sharing of the
electrons

Question 22

when are polar covalent bond made?

Answer 22

PCBs are formed when the electronegativity difference between the atoms is between 0.4 and around 1.7
Non-polar covalent bonds - difference is less than 0.4

Question 23

What makes a compound polar?

Answer 23

Bond polarity-Must contain polar bonds (dipole)
Symmetry -Molecule must not be symmetrical (needs to have overall dipole)
except Water- is polar
 CO2 is non polar

Question 24

why is polarity a desirible propertie in drugs?

Answer 24

1-More likely to be dissolved, required for gut absorption
2-Stay dissolved once administered intravenously

Question 25

what do phospholipids, contain?

Answer 25

Hydrophilic head- Polar head group
Hydrophobic tail- Mainly chains of C and H
Form important molecules (Cell membranes)

Question 26

what is a dative covalent bond

Answer 26

An atom donates two electrons to form a new bond

Question 27

what’s a dipole?

Answer 27

A pair of equal and oppositely charged or magnetized poles
separated by a distance

Question 28

what are Dipole-dipole interactions?

Answer 28

Electrostatic interactions
Permanent dipole (molecule with polarised bond)-Attracted to other molecules with permanent dipoles

Question 29

what is hydrogen bond?

Answer 29

Weak bonds
But stronger than D-D and VdW
Formed between Electron rich atoms (like N, O and F)
In water this is contributes to the high boiling point
can form lattices

Question 30

what are vander waals forces

Answer 30

can also be called London dispersion forces
These are weak interactions between molecules
Temporary dipoles
Where the electrons are unevenly distributed
Leads to polarization of neighbouring molecules

Question 31

what is intramolecular? and examples

Answer 31

exist or takes place within a molecule
ionic
covalent
metallic

Question 32

what is intermolecular?examples

Answer 32

existing or taking place between molecules
(nonbonding)
ion-dipole
Hbond
Dipole-dipole
ion-induced dipole
dipole induced dipole
Dispersion (London)

Question 33

what can electrons be describe as?

Answer 33

(Electrons are not discrete particles)
 Can be described as both particles or waves
 Impossible to locate precise position of an electron
 Possible to indicate a region where the electron is most
likely to be found
 This region is called an Orbital

Question 34

what drug interaction (with proteins) are driven by bonding?

Answer 34

Weak interactions like H-bonding
Other polar and hydrophobic interactions
AND shape

Question 35

what is orbital hybridisation and what does it do?

Answer 35

Atoms hybridise or ‘mix’ their atomic orbitals
-Optimise the geometry
-Minimise the energy

Question 36

what can hybrid orbital contain?

Answer 36

Hybrid orbitals may contain bonding
or non-bonding pairs of electrons

Question 37

what does the wedge and hash symbolise

Answer 37

Wedge – pointing towards you
Hash – pointing out to the back

Question 38

what affects bond length

Answer 38

Depend on the bonding situation
Bond length decreases as π character increases

Question 39

what affects the bond angles

Answer 39

Depends on…
 types of atom
 Bonds and lone pairs
 hybridisation

Answer 40

different spatial arrangements of the same molecule that can rotate along single bonds.(double and triple bonds can’t rotate)thermal energy is used to rotate

Question 41

what is The VSEPR ?

Answer 41

The VSEPR (Valence Shell Electron Pair Repulsion) theory in chemistry explains molecular geometry based on the idea that electron pairs around a central atom repel each other and therefore arrange themselves to minimize repulsion. It predicts molecular shapes by considering the number of electron pairs (bonding and non-bonding) around the central atom and arranging them to be as far apart as possible, leading to specific geometries such as linear, trigonal planar, tetrahedral, trigonal bipyramidal, and octahedral, among others.

Question 42

although conformers cannot be separated as separate structure, what is the energy difference between the structures?

Answer 42

30 kJmol –1