Atomic Radius, Nuclear Charge, Electron Shielding
What are the 3 things that affect first ionisation energy?
Increase. More protons- stronger attraction. Not much extra shielding.
What is the general trend in ionisation energy across periods? And why?
Decrease due to increased attraction between electrons and nucleus.
What is the trend in atomic radius across a period?
Increase due to metallic bonds getting stronger.
What is the trend in boiling points across metals?
Silicon. Strong covalent bonds.
Which element in period 3 has the highest melting point? And why?
Greater Van der Waals forces.
What do more atoms in a molecule mean for Van der Waals forces?
The noble gases. They are individual atoms.
Which elements have the lowest melting and boiling point? And why?
Simple molecular structure.
What bonding structure does phosphorus have?
2+ ions.
What ions do Group 2 elements form?
Increase. The lower the first and second ionisation energies, the more reactive the element.
What is the trend in reactivity down Group 2? And why?
Decrease. (Increased atomic radius, and the shielding effect)
What is the trend in ionisation energies down Group 2?
Hydroxides.
What do Group 2 elements produce when they react with water?
green, orange, brown
What are the colours of the halogens chlorine, bromine, and iodine? in order of question.
Decreases.
What is the trend in reactivity of halogens down the group?
Oxidising agents. They gain an electron in their outer shell, so they are reduced. This means that they oxidise other substances.
Are halogens oxidising or reducing agents? And why?
Add silver nitrate.
Which test can be done to check for halide ions?
Chlorine is white, Bromine is cream, Iodine is yellow.
What are the colours of the precipitates formed when chlorine, bromine, or iodine is present in the silver nitrate test?
Ag+(aq) + Cl-(aq)= AgCl(s)
What is the ionic equation for the silver nitrate test with Chlorine? Including state symbols?
2NaOH(aq) + Cl2(aq)= NaClO(aq) + NaCl(aq) + H20(l)
What is the equation to produce bleach? Including state symbols?
It is 3+ (group 1), 2+ (group 2), 1+ (group 3), -1 (group 5), -2 (group 6), -3 (group7)
How do you know what oxidation number an element will be at the start of the reaction?
A reaction where an element is simultaneously oxidised and reduced.
What is the definition of a disproportionation reaction?
Tetrahedral.
What is the molecular shape of NH4+ ?
109.5
What is the bond angle of a central atom with 4 electron pairs and no lone pairs, in degrees?
Non-linear, 104.5
What is the molecular shape and bond angle of H20, in degrees?
2.5
How much degrees does it go down by each time you add a lone pair to a central atom with 4 electron pairs?
Octahedral, 90
What is the molecular shape and bond angles of SF6, in degrees?
Trigonal planar, 120
If there are 3 electron pairs on the central atom, and no lone pairs, what is the molecular shape, and bond angle, in degrees?
Delocalised electrons pass kinetic energy to each other.
Why are metals good thermal conductors?
Because their metallic bonds are too strong to break.
Why are metals insoluble?
Because of the weak forces between layers.
Why does Graphite feel slippery?
Because the covalent bonds are too strong to break.
Why is Graphite insoluble?
Because water molecules are polar, so they pull ions away from the lattice and cause it to dissolve.
Why do ionic compounds dissolve in water?
The electrostatic attraction between two oppositely charged ions.
What is the definition of an ionic bond?
Electrons fluctuate, at one instantaneous moment, the electrons are more to one side of the atom. Causes a temporary dipole. Causes another temporary dipole in a neighbouring atom, then both are attracted to each other. ( or creates induced dipole where V
How do Van der Waals forces arise?
A repeating pattern of properties shown across different periods.
What is periodicity?
The attraction between an electron deficient hydrogen atom and a lone pair
What is the definition of a hydrogen bond?
A shared pair of electrons which has been provided by one of the bonding atoms .
What is the definition of a dative covalent bond (coordinate bond)?
Fluorine
What is the most electronegative element?
Ions
What cannot move in ionic solids?
The energy required to remove one electron from each atom in 1 mole of gaseous atoms to form 1 mole of gaseous 1+ ions.
Define the term 'first ionisation energy'?
Donates electrons and gets oxidised.
What does a reducing agent do?
Metals (except ammonia).
What are bases generally?
Acids.
What are proton donors?
OH- ions (Hydroxide ions).
What do soluble bases release in an aqueous solution?
H+ ions
What do acids release in an aqueous solution?
actual mass/predicted mass x 100
How do you calculate percentage yield?
The measure of the attraction of a bonded atom for the pair of electrons in a covalent bond.
What is the definition of electronegativity?
A difference in charge between two atoms caused by a shift in electron density in the bond.
What is a dipole?
The average mass of an atom of an element relative to 1/12th the mass of a carbon-12 atom.
What is the defnintion of relative atomic mass?
Elements with the same number of protons but different number of neutrons.
What is the defnition of an isotope?
Pale green, Orange, Violet
What are the colours of Chlorine, Bromine and Iodine in cyclohexane solution?
H+ ion has been replaced by metal ion.
Why is calcium an example of a salt?