chemFinal Flashcards
Across the period, how is atomic radii, first ionisation energy, and electronegativity affected (increase/decrease), and why?
All:
Proton no. increase, nuclear charge increase, shielding effect constant as number of principal quantum shells same
Individual:
Valence electrons pulled closer to nucleus, atomic radii decrease
Electron removed attracted stronger to nucleus, first ionisation energy general increase
Pull on bonding electrons stronger, electronegativity increase
Down the group, how is atomic radii, first ionisation energy, and electronegativity affected (increase/decrease), and why?
All:
More principal quantum shells, distance between valence electrons and nucleus increase
Individual:
Atomic radii increase
Electron removed attracted less strongly to nucleus, first ionisation energy decrease
Pull on bonding electrons weaker, electronegativity decrease
What are the three rules of electron configuration?
Electrons fill lowest energy orbital available first.
Orbital holds maximum two electrons with opposite spin.
Electrons fill all degenerate orbitals singly before occupying them in pairs.
What is the electron configuration up till 4s2?
What are the actual electronic configurations of noble gases as represented in the condensed electronic configurations?
Max config 1s2 2s2 2p6 3s2 3p6 4s2
[He] 1s2
[Ne] 1s2 2s2 2p6
[Ar] 1s2 2s2 2p6 3s2 3p6
Describe the relative radii of cations, anions and isoelectronic cation vs anion and the reasons.
Cation
Loss of electrons so loss of outer shell, remaining electrons attracted stronger to nucleus, radius smaller than parent atom
Anion
Extra electrons so greater repulsion between valence electrons, radius greater than parent atom
Isoelectronic cation and anion
Same electronic configuration, ion with more protons has higher attraction for electrons, cation radius smaller
Define ionisation
Removal of valence electrons from atoms in their gaseous states
Define electronegativity
Relative attraction atom has for shared electrons in covalent bond.
Write the first, second, and third, and first to third ionisation equations for element X.
X (g) → X+ (g) + e-
X+ (g) → X2+ (g) + e-
X2+ (g) → X3+ (g) + e-
X (g) → X3+ (g) + 3e-
Why do successive ionisation energies increase?
As electrons are removed, remaining electrons attracted more strongly, more energy needed to remove it.
Explain trend in successive ionisation energies between quantum shells.
Sharp increase in IE is between X and (X+1) IEs, so 1st electron removed from outermost quantum shell (n = Y), 2nd electron removed from inner quantum shell (n = Y-1), hence ? has X valence electron(s) and is in Group Z.
Explain trend in successive ionisation energies between subshells.
Slight sharp increase in IE is between X and (X+1) IEs, so last ? electron(s) attracted stronger to nucleus, so quantum shell divided into subshells occupied by ? and ? electrons respectively.
Explain decreasing anomaly in first ionisation energies @ B/Al.
Electron removed from B 2p subshell is further away from nucleus/at higher energy level than Be 2s subshell, less energy needed to remove it, IE decreases from Be to B.
Electron removed from Al 3p subshell is further away from nucleus/at higher energy level than Mg 3s subshell, less energy needed to remove it, IE decreases from Mg to Al.
Explain decreasing anomaly in first ionisation energies @ O/S.
Paired electron removed from O has interelectronic repulsion between 2 electrons in same 2p orbital, less energy needed to remove it, IE between N & O decreases. N has unpaired 2p electrons so no interelectronic repulsion.
Paired electron removed from S has interelectronic repulsion between 2 electrons in same 3p orbital, less energy needed to remove it, IE decreases from P to S. P has unpaired 3p electrons so no interelectronic repulsion.
Define oxidation & reduction.
Oxidation: gain of oxygen / loss of hydrogen / loss of electrons / increase in oxidation state
Reduction: loss of oxygen / gain of hydrogen / gain of electrons / decrease in oxidation state
Define disproportionation.
Same reactant oxidised & reduced to different substances simultaneously
Explain which substance has been oxidised/reduced during the reaction.
[reactant] is oxidised/reduced as oxidation state of [element] increases/decreases from [oldCharge] in [reactant] to [newCharge] in [product].
State & explain observation when aqueous chlorine/bromine is added to aqueous potassium bromine/iodine solution.
More reactive pale yellow Cl2 displaces Br from KBr, forming KCl and orange Br2. Pale yellow solution turns orange.
More reactive pale yellow Cl2 displaces I from KI, forming KCl and brown I2.
Pale yellow solution turns brown.
More reactive orange Br2 displaces I from KI, forming KBr and brown I2. Orange solution turns brown.
Name substances that test for reducing agents and results.
Test for oxidising agent:
Potassium Iodide
Test for reducing agent:
Potassium manganate (VII) (aq) (acidified): purple to colourless
Potassium dichromate (VI) (aq) (acidified): orange to green
Chlorine (test for bromine/iodine)
Name reducing agents
KI, H2, CO
Describe all VSEPR shape and bond angles
1 ep 0 lp linear 180
2 ep 0 lp linear 180
2 ep 1 lp v-shape bent <120
2 ep 2 lp v-shape bent «109.5
3 ep 0 lp trigonal planar 120
3 ep 1 lp trigonal pyramidal <109.5
4 ep 0 lp 109.5 tetrahedral
What affects gas diffusion in porous pot? Name gas exception and reason.
State and compare molar mass
Gases with lower molar mass diffuse faster
There are more [lighter] molecules leaving/entering ? than [heavier] molecules leaving/entering
Amount of gas and pressure inside pot increases/decreases, water level rises/falls
Ammonia is very soluble in water
