how electronic configuration vary across period?
across period, no. of e- in same quantum shell ↑, no. of quantum shells constant
how electronic configuration vary down group?
down group, no. of quantum shells ↑, no. of valence e- constant
how atomic/ionic radii vary across period?
radii ↓ >
↑ in no. of protons while shielding effect remains relatively constant due to same no. of inner shell e- >
nuclear attraction on valence e- ↑
how atomic/ionic radii vary down group?
radii ↑ >
↑ in no. of principle quantum shells, valence e- further from nucleus >
↑ in shielding effect outweighs ↑ in nuclear charge >
nuclear attraction on valence e- ↓
how 1st IE vary across period?
1st IE ↑ >
↑ in nuclear charge, shielding effect relatively constant due to same no. of inner shell e- >
nuclear attraction valence e- ↑ >
> energy req remove 1 e-
how ionic radii vary down group?
1st IE ↓ >
↑ in no. of principal quantum shells, valence e- further from nucleus >
shielding effect ↑ by more inner shell e- outweighs ↑ in nuclear charge >
< energy req remove 1 e-
how electronegativity vary across period?
↑; nuclear charge ↑, shielding effect relatively constant >
nuclear attraction on valence e- ↑, electronegativity ↑
how electronegativity vary down group?
↓; ↑ in no. of principal quantum shells, valence e- further from nucleus >
↑ in shielding effect outweighs ↑ in nuclear charge >
↓ nuclear attraction on valence e-, electronegativity ↓
what is trend in melting point from Na to Ar?
Na<Mg<Al; mp ↑>
↑ amount of energy req overcome ↑ strength of metallic bonds b/w respective metal cations, mobile delocalised e- as no. of delocalised e- ↑, charge density ↑ as atomic radii ↓
Si highest >
giant covalent structure, large amount energy req overcome strong covalent bonds b/w Si atoms
S8<P4<Cl2<Ar >
Cl2,P4,S8; simple molecular structure, Ar; simple monoatomic structure >
↓ amount of energy req overcome ↓ strength of id-id attractions b/w molecules as no. of e- per molecule to be polarised ↓ in same order
what is trend in electrical conductivity from Na to Ar?
Na<Mg<Al; ↑>
metallic bonding, delocalised valence e- act as mobile charge carriers >
no. of such e- ↑ from Na to Al
P4<Al<Si >
Si metalloid; semi-conductor w/ low conductivity
S8, P4, Cl2, Ar poor conductors, mobile charge carriers absent
why volatility of halogens decrease down the group?
down group, no. of e- to be polarised per molecule ↑ >
due to ↑ in quantum shells of inner e- >
↑ strength of id-id attractions b/w molecules, > heat energy required >
< volatile
state, explain variation in highest oxidation no. for oxides(Na->S) & chlorides(Na->P)
Cl most electronegative among P3 elements, O > electronegative than P3 elements >
P3 elements always +ve OS as lose e- >
max OS ↑ across period as > valence e- used for bonding in oxide >
P forms PCl3/PCl5 as can expand octet config using low-lying vacant 3d orbitals
state, explain variation in bonding in oxides(Na-S)
Na2O, MgO, Al2O3 giant ionic lattice;
SiO2 giant covalent structure;
P4O10, SO3 simple molecular structure >
bonding △ from ionic to covalent across period as electronegativity difference b/w P3 elements & O ↓
state, explain variation in bonding in chlorides(Na-P)
NaCl, MgCl2 giant ionic lattice;
AlCl3 ionic w/ covalent character;
SiCl4, PCl5 simple molecular structure >
bonding △ from ionic to covalent across period as electronegativity difference b/w P3 elements & Cl ↓ >
however AlCl3 is ionic w/ covalent character, high charge density of AlCl3, Al3+ distorts e- cloud such that there is orbital overlap b/w Al, Cl form covalent bonds
state reactions of oxides(Na-S) w/ water
Na2O(s) + H2O(l) → 2NaOH(aq)
MgO(s) + H2O(l) ⇌ Mg(OH)2(s)
Mg(OH)2(s) + aq ⇌ Mg2+(aq) + 2OH-(aq)
Al2O3(s) insoluble in water
SiO2(s) insoluble in water
P6O10(s) + H2O(l) → 4H3PO4(aq)
SO3(l) + H2O(l) → H2SO4(aq)
describe reactions of oxides(Na-S) w/ water
Na2O; react vigorously form strong alkaline pH 13-14
MgO; react small extent form Mg(OH)2(s) sparingly soluble, form weak alkaline pH 9
Al2O3; insoluble, high magnitude of lattice energy - energy evolved forming ion-dipole interactions insufficient overcome strong ionic bonds b/w oppositely charged ions
SiO2; insoluble, large amt energy req break many strong Si-O bonds
P6O10; react form acidic soln pH 2
SO3; react form strongly acidic soln pH 1
describe acid/base behaviour of oxides(Na-S)
Na2O(s) + 2H+ → 2Na+(aq) + H2O(l)
MgO(s) + 2H+ → Mg2+(aq) + H2O(l)
Al2O3 reacts w/ both acids, alkalis
Al2O3(s) + 6H+(aq) → 2Al3+(aq) + 3H2O(l)
Al2O3(s) + 2OH-(aq) + 3H2O(l) → 2[Al(OH)4]-(l)
SiO2 reacts ONLY w/ hot conc alkali due to GCS
SiO2(s) + 2OH-(aq) → SiO32-(aq) + H2O(l)
P6O10(s) + 12OH-(aq) → 4PO43-(aq) + 6H2O(l)
SO3(g) + 2OH-(aq) → SO42-(aq) + H2O(l)
explain acid/base behaviour of oxides(Na-S)
across P3, nature △ from basic>amphoteric>acidic >
bonding △ from ionic>covalent, electronegativity diff b/w P3 elements, O ↓ >
metallic oxides/hydroxides ionic, ionic oxides/hydroxides basic >
non-metallic oxides covalent, covalent oxides acidic >
ionic w/ covalent character amphoteric
describe, explain acid/base behaviour of hydroxides(Na-Al)
NaOH(s) + H+(aq) → Na+(aq) + H2O(l)
Mg(OH)2(s) + 2H+(aq) → Mg2+(aq) + 2H2O(aq)
Al(OH)3(s) + 3H+(aq) → Al3+(aq) + 3H2O(l)
Al(OH)3(s) + OH-(aq) → [Al(OH)4]-(aq)
describe reactions of chlorides(Na-P) w/ water
NaCl(s) + aq → Na+(aq) + Cl-(aq)
MgCl2(s) + 6H2O(l) → [Mg(H2O)6]2+(aq) + 2Cl-(aq)
[Mg(H2O)6]2+(aq) ⇌ [Mg(H2O)5OH]+(aq) + H+(aq)
AlCl3(s) + 6H2O(l) → [Al(H2O)6]3+(aq) + 3Cl-(aq)
[Al(H2O)6]3+(aq) ⇌ [Al(H2O)5OH]2+(aq) + H+(aq)
SiCl4(l) + 2H2O(l) → SiO2(s) + 4HCl(aq)
hot excess water
PCl5(s) + 4H2O(l) → H3PO4(aq) + 5HCl(aq)
cold excess water
PCl5(s) + H2O(l) → POCl3(l) + 2HCl(aq)
explain reactions of chlorides(Na-P) w/ water
NaCl; dissolve give neutral soln(low charge density, no hydrolysis) pH 7
MgCl2; dissolve give [Mg(H2O)6]2+, hydrolyses slightly(higher charge density) give slightly acidic soln pH 6.5
AlCl3; dissolve give [Al(H2O)6]3+, hydrolyses(high charge density) give acidic soln pH 3
SiCl4, PCl5; covalent chlorides hydrolyse completely give strongly acidic soln as HCl formed, pH 1-2 >
central atom has low-lying vacant 3d orbitals form dative bond w/ water by accepting lp of e- on O to form unstable transition state, break down form HCl
describe, deduce from E⦵ values, the relative reactivity of elements of Group 2 as reducing agents
down group, E⦵ value ↑ly -ve >
> readily oxidised >
reducing power ↑
describe, deduce from E⦵ values, the relative reactivity of elements of Group 17 as oxidising agents
down group, E⦵ value ↓ly +ve >
< readily reduced >
oxidising power ↓
what affects thermal stability of group 2 carbonates?
polarising power of M2+; larger charge density, greater ability polarise C-O bond of CO32-, bond weakened to larger extent
polarisability of anion; polarisability measures how easily e- cloud distorted by M2+, larger size of anion, greater its polarisability
describe, explain trend in thermal stability of Group 2 carbonates
down group, thermal stability ↑ >
ionic radius of M2+ ↑, charge density of M2+ ↓ >
ability of M2+ polarise large anion ↓, C-O bond weakened to smaller extent >
> heat energy req overcome stronger (bonds) idk what bonds
describe, explain trend in thermal stability of Group 17 hydrides
down group, thermal stability ↓ >
atomic radius ↑ from Cl to I >
bond length of H-X ↑ >
strength of H-X bond ↓ >
< heat energy req overcome weaker H-X bonds