Period 3 Yay Flashcards
Heat Na in dry Cl2 (g)
Reaction: vigorous? Flame? Eqn?
VERY vigorous burns with bright orange 🍊🍊🍊 flame 🔥🔥🔥
2Na (s) + Cl2 (g) -> 2NaCl(s)
Heat Mg with dry O2 (g)
Reaction: vigorous? Flame?
Very vigorous, white flame
Heating Na in dry O2(g)
Reaction - vigorous? Flame? Products?
Very vigorous
Burns with orange flame
4Na(s) + O2 (g) -> 2Na2O (s)
Sodium peroxide also produced: 2Na (s) + O2(g) -> Na2O2 (s)
Heat Mg with dry Cl2 (g) what do u get?
Vigorous reaction, burns with an intense white flame 💿💿💿💿
Mg (s) + Cl2 (g) -> MgCl(s)
Heat Al with dry O2 (g) ?
Very vigorous reaction at first, forming an inert Al2O3 (s) layer on the metal surface which prevents further reaction
4Al(s)+ 3O2 (g) -> 2Al2O3 (s)
Heat Al with dry Cl2 (g)
Vigorous reaction
2Al (s) + 3Cl2 (g) -> 2AlCl3 (s)
Si heat with dry O2 (g)
Slow reaction; needs to be strongly heated to about 400 degrees to form SiO2.
Si (s) + O2 (g) -> SiO2 (s)
Si heat with dry Cl2 (g)
Slow reaction
Si (s) + 2Cl2 (g) -> SiCl4 (l)
P4 (s) heat with dry o2 (g)
Vigorous? Flame?
In limited and in excess?
Vigorous reaction burns with white flame
In limited O2: P4 (s) + 3O2 (g) -> P4O6 (s)
In excess O2: P4 (s) + 5O2 (g) -> P4O10 (s)
P4 (s) heat with Cl2 (g)
Speed?
Excess and limited Cl2(g)?
Slow reaction
Limited Cl2: P4 (s) + 6Cl2 (g) -> 4PCl3 (l)
Excess Cl2: P4 (s) + 10Cl2 (g) -> 4PCl5 (s)
Heat S with dry O2 (g)
Vigorous reaction burns with pale blue flame
S (s) + O2 (g) -> SO2 (g)
SO2 reacts further with O2 to form SO3
2SO2 (g) + O2 (g) 2SO3 (g)
What is the trend in chlorides across period 3 in terms of structure?
Nacl and mgcl2 are solids, giant ionic high mp large amount of energy required to overcome strong electrostatic attraction between metal cations and chloride ions
Alcl3 (s) Sicl4 (l) Pcl5(s) Pcl3 (l)
Are simple covalents small amount of energy required to overcome the weak VDW forces between the discrete molecules
Trend of chlorides pH across period 3?
Na Mg Al Si P
7 6.5 3 2 2
Why oxidation numbers of Period 3 elements in chlorides always positive?
Chlorine more electronegative than the rest of the period 3 elements.
S does not form SCl6 even though it has energetically accessible vacant 3d orbitals. Why?
Steric hindrance - repulsion between electron clouds of the Cl atoms about the Central S atom as well as repulsion between bonding electrons.
However SF6 exists due to smaller size of F atom compared to the Cl atom.
Reaction of chlorides with water
NaCl (s) dissolves _________ in water to form ______ solution (pH = _)
Only _________ of ions (through ion-dipole interactions) takes place and __________ of Na+ does not occur as Na+ has low charge density, low polarising power
Readily Neutral 7 Hydration Hydrolysis
NaCl (s) -> Na+ (aq) + Cl- (aq)
Reaction of chlorides with water
MgCl2 dissolves _________ in water to form a w______ a_____ solution (pH = 6.5)
BOTH h________ of ions AND partial ___________ of Mg2+ (aq) occurs. Hydrolysis occurs due to polarisation of water molecules by the Mg2+ ion.
Readily
Weakly acidic
Hydration
Partial hydrolysis
- extent of hydrolysis less than that of Al3+ as Mg2+ has lower charge density than Al3+
2 eqns