Period 3 Flashcards
What happens to atomic radius across a period
Decreases: Increase in nuclear charge, same shielding, electron shells held closer to the nucleus
What happens to electronegativity across the period
Increases: Increase in nuclear charge, same amount of shielding, elements have an increased capability to withdraw electron density from a covalent bond
Why does melting point increase from Na to Al
The charge of the metal ion increases
The size of the metal ion decreases across the row
Increase in the strength of attraction between metal ions and delocalised electrons
Which P3 element has the highest melting point
Silicon- has a macromolecular structure with lots of covalent bonds which are very strong
What IMF do period 3 non-metals have
P4,S8 and Cl2 have simple molecule structures with IDD
Argon has the weakest IDD
Which P3 element has the highest boiling point and why
Once silicon has been melted most of its strong covalent bonds have been broken so boiling requires little energy. In the liquid state, Al has strong electrostatic attraction between ions and delocalised electrons and so requires a large amount of energy
Equation and PH for Sodium with water
2Na + 2H2O —> 2NaOH + H2
Ph- 13-14
Vigorous reaction- the metal fizzes rapidly and melts due to the heat released. A strong alkaline solution is formed
Magnesium with water
Mg + 2H2O —> Mg(OH)2 + H2
Slow reaction at room temp. Bubbles of gas are produced, only a weak alkali as magnesium hydroxide is only sparingly soluble
PH= 9-10
Magnesium with steam
Mg + H2O —> MgO + H2
occurs a lot faster due to the temperatures needed to generate the steam
Chlorine’s two reactions with water
1: Cl2 + H2O [reversible symbol] —> HClO + HCl
Ph= 2-3
2. In the prescence of bright sunlight
2Cl2 + 2H2O —> 4HCl + O2
PH= 2-3
Reaction of Sodium with Oxygen
For simple oxide: 2Na + 0.5O2 —> Na2O
For peroxide: 2Na + O2 —> Na2O2
Burns brightly in O2 to form a characteristic yellow flame and a white solid
magnesium with oxygen
2Mg + O2 —> 2MgO
burns brightly with a white flame that forms a white solid
Aluminium with oxygen
4Al + 3O2 —> 2Al2O3
Burns with a bright white flame to produce aluminium oxide.
Ph= 7
Silicon and oxygen
Si + O2 —> SiO2
PH- 7
Phosphorous and oxygen
Two different forms of phosphorous: red phosphorous with chains of P4 tetrahedrons
White phosphorous which is single P4 tetrahedral molecules
P4+5O2–> P4O10
Sulfur and oxygen
S + O2 —> SO2
Why does MgO have the highest melting point
MgO has ionic bonds where strong electrostatic attraction between oppositely charged ions, these require a lot of energy to overcome
Why does Al2O3 have more covalent character than MgO
Al3+ is smaller than Mg2+, meaning it is more polarising which distorts the electron cloud around the o2- ion more so that there is more electron density shared between the two ions
Sodium oxide with water
Na2O + H2O —> 2Na+ + 2OH-
Ph= 13-14
Magnesium oxide with watee
MgO + H2O —> Mg(OH)2
Aluminium and silicon oxide are both insoluble in water so what is there ph?
7
Potassium oxide with water
P4O10 + 6H2O —> 4H3PO4
Ph- 1-2
Sulfur dioxide with water
SO2 + H2O —> H2SO3
Ph- 2-3
Sulfur trioxide with water
SO3 + H2O —> H2SO4
Ph- 0-1
Sodium oxide and H2SO4
Na2O + H2SO4 —> Na2SO4 + H2O
Magnesium oxide with HCl
MgO + 2HCl —> MgCl2 + H2O
Amphoteric oxides, HCl and NaOH : Al2O3
Al2O3 + 6HCl —> 2AlCl3 + 3H2O
al2O3 + 2NaOH + 3H2O —> 2NaAl
Phosphoric acid and NaOH and phosphorus oxide
H3PO4 + 3NaOH —> Na3PO4 + 3H2O
P4O10 + 12NaOH —> 4Na3PO4 + 6H2O
Reaction of sulfur dioxide in solution
SO2 + 2NaOH —> Na2SO3 + H2O
P4O10 + 6Na2O
4Na3PO4
P4O10 + 6MgO —>
2Mg3(PO4)2
Explain why magnesium has a higher melting point than sodium
Mg has a greater charge of 2+, meaning there is a stronger electrostatic attraction between positive metal ions and delocalized electrons
A sample of the highest oxide of phosphorous was prepared in a laboratory. describe a method for determining the melting point of the sample- state how the result could be obtained to evaluate its purity
sample in a suitable melting point apparatus- heat slowly to establish the boiling point- lower melting point indicates impurities
state the structure of and bonding in silicone dioxide, other than high melting point, give 2 physical properties
Structure: Macromolecular
Bonding: Covalent
property: Brittle, doesn’t conduct
give the formula of the species in a sample of solid phosphorous oxide. state the structure and bonding
formula:P4O10
structure: molecular
Bonding: Shared paired of electrons/bonding
Equation for the reaction between SO2 and H2O
SO2 + H2O –> H+ + HSO3
state the type of bonding in magnesium oxide, outline a simple experiment to demonstrate that magnesium oxide has this type of bonding
melt it and see if it can conduct electricity
Why is silicon dioxide insoluble in water
macromolecular structure with strong covalent bonds between molecules- water cannot break hydrogen bonding
the melting point of P4O10 compared to silicon dioxide
lower- is a simple molecule with weak covalent bonds between molecules, covalent bonds are stronger in SiO2 so requires less energy to overcome in P4O10- doesn’t require much energy to break the IDD
Equation for magnesium oxide acting as a base
MgO + 2HCl –> MgCl2 + H2O
phosphorous oxide with sodium hydroxide
P4O10 + 12NaOH –> 4Na3PO4 + 6H2O
state the type of bonding in these basic oxides, explain why this causes them to have basic properties
Ionic- Contains O2- which can form OH- in water
sulfur dioxide and water
SO2 + H2O –> HSO3- + H+
suggest why sulfur dioxide forms a weakly acidic solution
Reaction is in equilibrium- it is a reversible reaction
explain why siO2 is described as an acidic oxide even though it is insoluble in water
SiO2 reacts with bases
explain why phosphorous oxide has a higher melting point than sulfur oxide
P4O10 is a larger molecule, more electrons
phosphoric acid and magnesium oxide
3H3PO4 + 2MgO –> Mg3(PO4)2 + 3H2O
why does SO2 have a low melting point
weak induced dipole dipoles between molecules
Na2O and P4O10
6P4O10 + Na2O –> 4Na3PO4
observation when su;fur burns in oxygen
pale blue fame and fumy gas- has covalent bonding
Al2O3 and HCl
Al2O3 + 6HCl –> 2Al2+ + 3H2O
Al2O3 and sodium hydroxide
Al2o3 + 2OH- __. 3H2O + 2Al(OH)4
lithium melting point higher or lower than sodium oxide
lower- stronger attraction to O2-
Na2O and P4)10 - what reaction
6Na2O + P4O10 –> 4Na3PO4
acid base
property of aluminum oxide coating that causes aluminum to resist the corrosion of water
insoluble
why does silicon dioxide not react with HCl but does with sodium hydroxide
SiO2 + 2NaOH –> Na2SiO3 + H2O
two equations to show how vanadium oxide acts as a catalyst in this process
1: V2O5 + SO2 –> V2O4 + SO3
2: V2O4 + 1/2O2 –> V2O5
