Period 3 Flashcards
(21 cards)
Why is sodium more reactive than magnesium
When they react they loose electrons
Na requires one electron to be lost where mg requires 2 electrons to be lost
Reaction of sodium and water
2Na + 2H2O = 2NaOH + H2
1. Alkaline solution of NaOH as NaOH is a strong base
2. Reacts with cold water to form a ball ( vigoursly )
3. Fizzes with gas of H2 produced
Reaction of magnesium with water(l)
- Mg(OH)2 reacts slow with cold water forming weak alkaline solution
- Sparingly soluble so little OH ions
Reaction of magnesium with water(g)
Mg + H2O(g) = MgO(s) + H2 (g)
1. Much faster reaction than liquid water
2. forms white ppt of MgO and bright light
Sodium and oxygen
Na + 1/2 O2 = 2Na2O= very fast = orange flame and white ppt
Magnesium and oxygen
mg +1/2O2 = mg O = very fast bright white flame and white ppt
Aluminium and oxygen
2Al + 3/2O2 = Al2O3= slow but fast if powdered sprinkle alumunim powder then you get bright light sparks
Silicon and oxygen
Si + O2 = SiO2 = slow orange flame and white solid
Phosphorus and oxygen
P4 + 5O2 = p4O10 = spontaneously combusts white flame and white fumes
Sulfur and oxygen
S + O2 = SO2 ( with a high temperature and catalyst SO3 can be made ) = steadily burns pale blue flames and colourless gas
Structure and bonding in Na2O,MgO,Al2O3
all form giant ionic lattices with strong electrostatic forces of attraction between positive metal ions and negative oxygen ions. They have high mp and no therefore all are very fast when they react
Why does sodium oxide have a lower melting point than magnesium oxide?
Sodium has a OnePlus charge, whereas magnesium has a 2+. Magnesium 2+ a smaller ionic radius there are greater attraction to the oxide ion
Why does aluminium oxide have a lower melting point than magnesium oxide?
Aluminium 3+ has a smaller ionic radius than magnesium 2+ therefore more polarrising. This distorts the electron cloud around oxygen so therefore more electron density shared between two ions.
Silicon Oxide melting point
Has covalent bonding forms in macro molecular structure so has strong covalent bonds between atoms therefore requires a lot of energy to overcome
Phosphorus oxide and sulphur dioxide
They both have covalent bonding perform simple molecular structure with weak induced dipole first of attraction between molecules. One of them has more electrons therefore greater induced typo forces of attraction
SO2 in acid base reactions
H2SO3
SO3 and acid base reactions
H2SO4
P4O10 in acid base reaction
H3PO4
Displayed formula of SO3
What dues amphoteric mean?
Reacts as an acids and bases
How does Al2O3 act as a amphoteric oxide
Al2O3 + 6HCl = 2AlCl3 + 3H2O
Al2O3 + 2NaOH + 3H2O =2NaAl(OH)4
