period 3 Flashcards
trend of atomic radius across period 3
decreases along period as there is am increase in nuclear charge and same amount of shielding this means electron shells are held closer to the nucleus
trend in electronegativity across peroid 3
increases along the period as there is an increase in nuclear charge and same amount of shielding so elements are increasingly capable of withdrawing electron density from a covalent bond
trend and breaks in trend in first ionization energies across the period 3
increases along period as there is an increases in nuclear charge and same amount of shielding so electron are held increasingly more tightly and so require more energy to be removed.
Al has a lower first ionization energy the mg because mg has a 3s electron removed and al has a 3p electron removed and 3p is higher in energy than 3s
S has a lower first IE than P as P has a 3p electron removed which is unpaired and S has a 3p electron removed that is paired so S has a lower IE due to electron pair replusion
trend in melting and boiling point across period 3
MP increases from Na to Al because the charge on the metal ion increases from Na+ to Al3+, the size of the metal ion decreases across the row therefore there is an increases in the strength of attraction between the metal ions and delocalized electrons.
silicon has highest MP because it has a macromolecular structure with lots of covalent bonds which are very strong.
for the non-metals P4, S8 and Cl2 all have simple molecular structure with IDD intermolecular forces, the strength of the IDD depends on the size of the molecule and S8 is largest followed by P4 then Cl2, argon exist as single atoms with the weakest IDD out of all of them.
aluminum has the highest BP because once silicon has been melted most of its strong covalent bonds have been broken so only requires little extra energy, in the liquid state aluminum still has strong electrostatic attraction between ions and delocalized electrons so requires a large amount of energy to boil
reaction of Na with water
2Na(s) + 2H20(l) –> 2NaOH(aq) + H2(g)
vigourous reaction, fizzes rapidly due to heat released
strongly alkinaline soloution
reaction of Mg with water
Mg(s) + 2H20(l) –> Mg(OH)2(aq) + H2(g)
slow reaction at room temp
weak alkali solution formed as magnesium hydroxide sparingly soluble
reaction of sodium with oxegon
2Na(s) +1/2O2 (g) –> Na2O(s)
reaction of magnesium with oxegon
2Mg(s) +O2 (g) –> 2MgO(s)
reaction of alumunium with oxegon
4Al(s) +3O2 (g) –> 2Al2O3(s)
reaction of silicon with oxegon
Si(s) +O2 (g) –> SiO2(s)
reaction of phosphorus with oxegon
P4(s) +5O2 (g) –> P4O10(s)
reaction of sulphur with oxegon
S(s) +O2 (g) –> SO2(s
2S(s) + 3O2(g) —>2SO3(s)
types of bonding present in period 3 oxides Na-S
oxides of sodium, magnesium and alumumium are all ionic, al oxide has a large amount of covalent character though as the al3+ is very polarising and larger O2- is very polariasable
silicon dioxide has a giant macromolecular structure, very stromg covlent bonds, very high melting point, major component in glass and sand
oxides of phosphourusand sulfur are simple molecualr, so melting and bioling point dependepent stength of intermolecular forces
reaction of sodium oxide with water ad pH of solution fomred
Na2O(s) + H2O(l) –> 2Na+(aq) +2OH–(aq)
pH 12-13
reaction of Mg oxide with water and pH of solution fomred
MgOs) + H2O(l) –> Mg(OH)2(aq)
pH 9-10
