Transition work

What is ATP

1atm + 20°C

Why are yields not 100%

• reversible reactions → balance between reactants + products

• unexpected/unwanted reactions

• product loss during transfer → purification/filtration

• Reactant may be impure so started with a lower mass

• The reaction may not be finished(unreacted)

Why is atom economy important

less resources + energy is wasted

what is the structure of an atom

• tiny central nucleus(protons + neutrons)

• electrons in energy shells

• most of the atom is empty space

What is the timeline of the discovery of the atom

• Thompson - Plum pudding - 1897

• Rutherford - Nuclear(nucleus) - 1911

• Bohr - Nuclear(shells) - 1913

• Chadwick - nuclear(neutrons) - 1932

what is relative atomic mass

the average mass of an element compared to a standard mass of carbon-12

What is the electronic structure

• shells are made up of subshells - each subshell is made up of orbitals

• each orbital holds 2 electrons(have an opposite spin - up/down)

• Don’t know the exact location of electrons(cloud of negative space) but are in the orbitals

subbshells + electron configuration

• Subshells - S, P, D, F

• S-1, P-3, D-5,-7

• S - spherical P - dumbbell/ two lobed

electron configuration

• Shell,subshell,no.electrons eg

N→1s²2s²2p³

what is Aufbau’s principle

Electrons enter the lowest energy orbital available

What is Hund’s rule

Electrons prefer to occupy orbitals on their own and only pair up when no empty orbitals of the same energy are available

How to add electrons

• Fill in order of increasing energy

• When there is more than one orbital at the same energy level single then double

• hold up to 2 electrons

• (different subshells have different orbitals)

what is dative covalent bonding

A covalent bond in which the shared pair of electrons has been supplied by one of the bonding atoms only

what is a polar bond

uneven distribution of electrons around the bond

what is a polar molecule

uneven distribution of electrons around a molecule

what is electronegativity

• ability of a particular atom to attract electrons to itself

• why electrons in a covalent move towards one atom more than another

factors that affect electronegativity

• nuclear charge - more protons → more attraction between nucleus + bonding pair of electrons

• atomic radius - closer to the nucleus → stronger attraction between nucleus + bonding pair of electrons

• Shielding - Less shells of electrons → less shielding(repulsion) so stronger attraction between nucleus + bonding pair of electrons

trend of electronegativity down the group

• electronegativity decreases

• atomic radius increases

• more shielding

• less attraction between nucleus + bonding pair of electrons

trend of electronegativity across a period

• electronegativity increases

• atomic radius decreases

• more nucleus charge

• stronger attraction between nucleus + bonding pair of electrons

trend of size of atom across a period + down the group

• group - size increases as you go down

• period - side decreases as you go across

What is a dipole and why

A molecule with an unequal electron distribution

due to

• different nuclear charges

• atoms are different sizes

• shared pair of electrons closer to one atom then another

delta symbols

• delta positive/negative charge as (delta-small) because only a shift of electrons so not large difference in charge n

Trend of electronegativity as MPT decreasing

• electronegativity decreases

• +ve ion gets smaller

• more charged

• -ve ion more polarised

polarity of water

• polar bonds

• polar structure - bent structure, don’t oppose

polarity of carbon dioxide

• polar bonds

• non-polar structure - linear structure - oppose

what do physical properties depend on

structure

what are molecules with regular arrangement(lattice) called

crystals

what are the 4 types of crystals

• ionic - lattice of negatively + positively charged ions

• metallic - regular lattice of positively charged metal ions surrounded by a sea of delocalised electrons

• macromolecular(giant covalent) - regular lattice of atoms held together by covalent bonds

• molecular( simple covalent) - regular lattice of covalently bonded molecules held together by intermolecular forces

what are bonding pair and lone pair

• bonding pair - electrons in a covalent bond

• lone pair - electrons not involved bonding

how to draw structures

what determines the basic shape of molecules

• number of electrons pairs around the central atom

what is bond length + bond angle

• bond length - distance between the nuclei of two bonded atoms

• bond angle - the angle between two covalent bonds

how to calculate amount of lone pairs

total no. electron pairs - bonding pairs = lone pairs

general formula

the simplest algebraic formula of a member of a homogenous series

homologous series

a series of organic compounds having the same functional group but with each successive member different by CH2

functional group

group if atoms responsible ofr the characteristic reactions of a compound

nomenclature for organic compounds

• stem - longest continuous chain of carbons

• functional groups - prefix/suffix

• if a compound has a branch - alkyl group

• shortest path to a branch and count branch chain length

display formula

relative positions of all atoms + bonds

structural formula

minimal detail arrangement what is attached to each C atom

molecular formula

no. + type of atom of element( not show how are joined/structure)

empirical formula

simplest whole number ratio of atoms of each element

general formula

simplest algebraic formula for any member of a homologous series

skeletal formula

H+C atoms not shown unless functional group

• junction → carbon missing

• bonds → hydrogen