Chemistry

Question 1

What are the learning objectives

Learning approach
Name 1
Name 3
Name 5
Name All

Answer 1

Understand the fundamentals of atomic structure

Understand the fundamentals of bonding

Explain the difference between σ and π bonds

Appreciate that molecules are 3-dimensional

Show that their shape affects their interactions with receptors

Predict the shape of molecules with reference to hybridisation

Question 2

What is an atom

Answer 2

An atom is the simplest particle of matter that represents an element based on properties such as the number of protons and electron it has

Question 3

what are the 3 components of the atom and where are they located

Answer 3

Nucleus

• Proton
• Neutron

Electron Shells
- Electrons

Question 4

in a neutral atom describe the balance of protons and electronsand what happens if they fall out of balance

Answer 4

they are equal, if they fall out of this balance they then become charged ions with either a positive or negative charge depending n if they have gained or lost electrons

Question 5

How are electron’s arranged

Answer 5

they are aranged in shells and within them subshells,

the orbital can only contain so many electrons

Standard shells defined as 1,2,3,4

Orbital defined as s,p,d,f

each subshell

As a shell gets bigger there is a new subshell added

Question 6

describe the rule involving the subshells with the 3rd and 4th subshell

Answer 6

4s comes before 3d

Question 7

Name how many electrons are held within each different type of shell (s,p,d and f)

Answer 7

S = 2
p = 6
d = 10
f = 14

Question 8

Define Ionic bond

Answer 8

electrostatic forces of attraction that occur, when one atom loses an electron and one atom gains an electron (or more)

Question 9

What is the general rule that ions follow

Answer 9

they are aiming to achieve complete outer shells

so if the atoms outershell is the 2nd shell then it needs to fill its P orbital completely

or go down to the 1st shell depending on how many ions need to be gained or lost

Question 10

Describe what a covalent bond is

Answer 10

covalent bond means to share electrons as seen in methane or other alkane substances

Question 11

Describe the shape of carbons covalent bond

Answer 11

tetravalent

Question 12

Describe the hybridisation theory

Learning approach:

Summed up
Then Into a worked example using carbon

Answer 12

We start with a molecule that is trying to achieve the same energy electrons

To do this it promotes an electron form one of the lower shells

from there we have electrons which are not paired and ready for bonding however they arent of the same energy

so they become hybridised to allow for the bonding to occur

SUMMED UP: Hybridisation occurs to allow molecules that has electrons at uneven energy levels to bond to other molecules covalently to achieve noble gas configuration

Question 13

Define a sigma bond

Answer 13

a bond formed by the overlap of orbitals in an end-to-end fashion, with the electron density concentrated between the nuclei of the bonding atoms and is the strongest form of covalent bond

Question 14

Define a pi bond

Answer 14

chemical bonds that are covalent in nature and involve the lateral overlapping of two lobes of an atomic orbital with two lobes of another atomic orbital that belongs to a different atom

Question 15

Describe what the different forms of hybridisations as well as the description of the shape of these molecules

Learning approach
sp3
sp2
sp1

Answer 15

Sp3 = 4 single bonds forming 109 degree known as tetravalent

sp2 = when there are 2 single bonds and one double bond forming angles of 120 often known trigonal planar

sp = when there are 1 single bond and a tripple bond forming bond angles of 180 and it is known as linear

Question 16

Define the term constitutional isomer

Answer 16

Constitutional isomers (structural isomers)

are molecules with the same molecular formula but have a different connectivity of atoms, which gives rise to different chemical and physical properties

Question 17

Define the term stereoisomer and name the two different types

Answer 17

Molecules with the same molecular formula and the same connectivity of atoms but a different arrangement of atoms in space

diastereoisomers, Enantiomers

Question 18

Define the term enantiomer

Answer 18

A form of stereoisomers that is non super impossable on their mirror image where one enantiomer is labelled (r) and one (s)

Question 19

What is a racemic mixture

Answer 19

A mixture when both enantiomers are present in equal amounts

Question 20

Define the Cahn ingold prelog rules

Answer 20

We rank four substitutents around the chiral centre from 1->4

lowest rank groub is orientated furthest from observer according to atomic number

then decrease in priority in clockwise direction is R

counter clockwise is S

Question 21

describe cis trans isomers

Answer 21

Trans is different side
Cis is same side

Question 22

describe how we use e/z isomerism

Answer 22

Divide alkene in two perpendicular to the double bond

Rank substituents using CIP rules

If two highest opposites it is designated E isomerism

If two highest same it is designated Z

Question 23

describe what a functional group is

Answer 23

an atom of group of atom that has similar chemical properties when it occurs in different compounds defining the characteristic physical and chemical properties of organic compounds