8 Periodic Table Flashcards
Periodic trend
Across period, atomic radii decreases
increase in nuclear charge, shielding effect by inner pqs remains relatively constant -> increase in effective nuclear charge
Group trend
Down a Group, atomic radii increase
increase in nuclear charge cancelled out by increase in shielding effect
Since more pqs, larger atomic radius
Electrical conductivities across Period 3
Na, Mg, Al:
Electrical conductivities are high (giant metallic lattice structures)
Increases from Na to Al (number of delocalized electrons increases from Na to Al)
Si:
Electrical conductivity decreases sharply
Giant covalent structure (But is a semi-conductor)
P4, S8, Cl2, Ar:
P to Cl have simple covalent structure
Ar has a monoatomic structure
No mobile charge carriers
IE across Period
Generally increases except:
Group 2-13 and Group 15-16
Melting point across Period 3
Na, Mg, Al:
Fairly high (giant metallic lattice structures), increases from Na to Al (number of valence electrons increases from Na to Al)
Si:
Highest melting point (giant covalent structure)
P4, S8, Cl2, Ar:
P to Cl have simple covalent structure
Ar has a monoatomic structure
Low melting points
S8>P4>Cl2>Ar
Greater number of electrons in molecules=Stronger id-id interactions
Reaction with NaCl and water
Dissolves readily to form neutral solution (pH=7)
Only hydration of ions occurs
No hydrolysis of Na+ -> low charge density of Na -> low polarising power
Reaction with MgCl2 and water
Dissolves readily to form weakly acidic solution (pH=6.5)
Hydration of ions occurs
Partial hydrolysis of Mg2+ occurs
Reaction with Al2Cl3 and water
Dissolves readily to form acidic solution (pH=3)
Hydration of ions occur
Substantial hydrolysis of Al3+ occurs
Reaction with SiCl4 and water
Dissolves to form a strongly acidic solution (pH=2)
Hydrolysis occurs due to energetically accessible vacant 3d orbitals for dative bonding
Reaction with CCl4 and water
No reaction (does not undergo hydrolysis)
Smaller size of C atom as compared to Cl atom hinders approach of water molecules
C does not have energetically accessible vacant 3d orbitals
Reaction with PCl5 and water
Undergoes hydrolysis to give strongly acidic solution (pH=2)
P atom uses energetically accessible 3d orbitals for dative bonding with water molecules
Reaction with Na2O and water
Reacts vigorously to from NaOH(aq) which is strongly alkaline (pH=13)
Reaction with Na2O and acid/base
Na2O is basic -> no reaction with base
Reacts with acid to form salt and water
Reaction with MgO and water
Reacts vigorously to from Mg(OH)2(aq) which is weakly alkaline (pH=8)
Reaction with MgO and acid/base
MgO is basic -> no reaction with base
Reacts with acid to form salt and water
Reaction with Al2O3 and water
Insoluble
Energy released during hydration < energy required to overcome strong electrostatic forces of attraction between Al3+ and O2-
Reaction with Al2O3 and acid/base
Al2O3 is amphoteric
Reacts with both to give salt and water
Reaction with SiO2 and water
Insoluble
Large amount of energy required to break covalent bonds
Reaction with SiO2 and acid/base
SiO2 is acidic
Reacts with concentrated alkali to give salt and water
Reaction with P4O10 and water
Reacts violently with water to form acidic solution (pH=2)
Reaction with P4O10 and acid/base
P4O10 is acidic
Reacts violently with alkali to give salt and water
Reaction with SO3 and water
Reacts wo form acidic solution (pH=2)
Reaction with SO3 and acid/base
SO3 is acidic
Reacts with alkali to give salt and water
Thermal decomposition of Group 2 carbonates, nitrates and hydroxides
Metal cation polarizes large electron cloud of anion to such an extent that the covalent bond of the anion is weakened
Down the Group, atomic radius increases -> charge density decreases -> polarizing power decreases -> covalent bonds of anion weakened to a smaller extent
Boiling points down Group 17
Down the Group, number of electrons increases, more energy required to overcome stronger id-id interactions, increase in boiling point and decrease in volatility
Oxidizing power down Group 17
Decreases down a group
Solubility of hydrogen halides
Dissolves in non-polar solvent (retains covalent character)
Dissolves in polar solvents (dissociates to form strong acids)
Boiling points of hydrogen halides
HF (exception): highest due to presence of stronger hydrogen bonds
Down the Group: increases due to larger number of electrons -> stronger id-id interactions
Thermal stability of hydrogen halides
Decreases due to decreasing bond energy
Bond length of hydrogen halides
Increases down the group
