Summary-Unit 1 Chemistry

Atomic Structure

Fundamental particles=electrons, neutrons, protons
Proton charge=+1, why hydrogen is sometimes called/used as a proton
Electrons charge=-1
Protons and neutrons held together by a nuclear force
Electrons held by electrostatic forces
Mass of proton=1.673x10-27
Mass of neutron=1.675x10-27
Mass of electron=0
Shells fill up- 2,8,18
Atomic number=proton number
Mass number=no. of protons + no.of neutrons
Isotope=same number of protons but different number of neutrons
Isotopes react in the same way because they have the same electron configuration
Mass spectrometer kept in a vaccum so ions do not react with air molecules
Sample in gaseous state so it can be injected directly
Ionisation-elctron gun fires high speed electrons, knocks out an electron
Acceleration-negatively charged plates, lighter ions travel faster
Deflection-magnetic field, lighter ions and 2+ ions deflected more,

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Detection- ions strike detector, gain an electron, lose charge, create current relative to abundance
S orbital=2
P orbital=3x2=6
D orbital=5x2=10
Orbitals of lower energy are filled out first
Orbitals fill singly and then pair up due to electron repulsion theory
Ionisation energy-energy required to remove 1mole of electrons from 1 moles of atoms in gaseous state
Second IE is higher than the first, as an electron is being removed from a positive ion

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The relative atomic mass is the weighted average mass of an atom of an element relative to 1/12 the relative atomic mass of an atom of carbon-12
Moles=mass/molar mass
Moles=concentration x volume
Ideal gas equation=PV=nRT, volume in m3
C to K: +273
1 dm3=1000cm3
Atom economy= Mass of desired/ total mass of reactants x100
Percentage yield=number of moles of specified product/ theoretical number of moles of product x100

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Ionic-between non metals and metals, transfer of electrons, held together through electrostatic attraction between oppositely charged ions
Covalent-non metals only, a shared pair of electrons. Held together by electrostatic attraction between psotive nuclei and shared electrons
Dative Covalent-one atom provides both electrons, e.g. ammonium ion
Metallic-metals only, postive ions attracted to the sea of delocalised electron,Mg3+=3 electrons
Crystals: Molecular, Macromolecular,Giant Ionic Lattice, Metallic
Electronegativity is the power of an atom to attract electron density to itself in a covalent bond
Intermolecular:
- Van De Waals
- Dipole Dipole
- Hydrogen Bonding

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Most electronegative elements- F,O, N
Ice is less dense than water as molecules are more spread out
Turning a solid to liquid=fusion. Energy supplied to do this is called enthalpy change of fusion
Liquid to gas=vaporisation. Energy supplied to do this is called enthalpy change of vaporisation
2 electrons=linear=180
3 electrons=no lone pairs=trigonal planar=120
- 1 lone pair=non linear trigonal planar=120
4 electrons=no lone pair=tetrahedral=109.5
- 1 lone pair=trigonal pyramidal=107
5 electrons=no lone pairs=trigonal bypyramid=120, 90
6 electrons= no lone pairs=octahedral= 90
Repulsion theory
- lone pair-lone pair
- lone pair-bonding pair
- bonding pair-bonding pair
Every lone pair takes 2 degrees off bond angle

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Period 3 Trends:
- Na, Mg, Al- giant metallic=high b.p, increase across as the charge on the ion increases
- Si-macromolecular=high b.p
- P, S, Cl- molecular, order S8>P4>Cl2, depends on number of VDW+size of molecule
Atomic radii decreases across a period due to increased nuclear charge, which pulls electrons closer to the nucleus and there is no extra sheilding
Atomic radii increases down a group due to extra shielding and distance from the nucleus
First ionisation energy=the energy required to convert 1 mole of isolated gaseous atoms into 1 mole of singly positive gaseous ions
For example: Na(g)-->Na+(g)+e-
First ionisation energy increases across a period due to increased number of protons, nuclear charge, therefore its increasingly harder to remove an electron
First ionisation energy decreases down a group, increased shielding and distance from the nucleus, easy to remove

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Drop in ionisation energy-groups 2 and 3
- Mg loses a 3s electron
- Al loses 3p electron
- P electron is already higher energy than the s, so its easier to remove
Drop in ionisation energy- groups 5 and 6
- P has no paired electrons because each p electron is in a different p orbital
- S has 2 p electrons paired, so one is easier to remove due to electron repulsion theory
There is a little increase in the first and second ionisation energy because in the second an electron is trying to be removed from a positive ion, which is harder

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Organic chemistry=carbon compounds
Structural formula-unique arrangement of atoms in a molecule without showing the bonds
Functional Groups
- Alkanes=ane Alkenes=ene Haloalkanes
- Alcohols=ol Aldehydes=al Ketones=one
- Carboxylic acid=oic acid
A homologous series is a family of organic compounds Isomers=molecules that have the same molecular formula but arranged differently
- Same general formula
- Show trends in physical properties e.g b.p
Structural isomerism=same molecular formula but different structural formula
- Positional=functional group attached to main chain at different points
- Functional group=the functional group is different
- Chain=different arrangement of hydrocarbon chain e.g. branching

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Saturated hydrocarbons
CnH2n+2
Can be unbranched chains, branched, cycloalkanes
Almost non polar because there is only a small difference in electronegativity
B.p increase with chain length
Branched alkanes have lower b.p as there more spread out, VDW are less effective
Alkanes are insoluble in water
Relatively unreactive
Crude oil is seperated through fractional distillation
Cracking is done to create more useful products and some of the products are alkenes which are more reactive
Thermal cracking=done under high temp and pressure, C-C bond is broken in a way where one electron(free radical) goes to each carbon. There is not enough H, so one of the products is an alkene
Catalytic cracking=lower temp and pressure compared to therma, uses a zeolite catalyst(honeycomb structure), mainly produces motor oil

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