Group 15 Flashcards
Name the group 15 elements
Nitrogen, Phosphorus, arsenic (As), antimony (Sb), bismuth (Bi)
Which are metals, non metals and metalloids?
N and P - non metals
As - metalloid
Sb and Bi - metals
What is the most stable phase of phosphorus? Give two other examples of structures it adopts
Most stable is black phosphorus - sheets of puckered fused P6 rings
other examples :
-White phosphorus - P4, tetrahedral
-Red phosphorus - more complex structure
Describe the structure of metallic arsenic
layers of puckered As6 rings, similar structures for Sb and Bi
How will N2 react with Li and Mg?
It will be reduced by Li and Mg (powerful reducing agents) to form the corresponding nitrides
Describe the reactivity of P4
P4 (white phosphorus) is very reactive, spontaneously flammable in air
- will react at 300C and inert atmosphere to produce red phosphorus which is much less reactive (no strained ring structure)
- will react at over 800C to produce P-P triple bonds
Describe the stability of the Nitrogen halides
NF3 is the only stable halide of nitrogen. The rest are thermodynamically unstable.
Describe the reactivity of the halides of Phosphorus (hydrolysis)
PX3 are hydrolysed by H2O, hydrolysis is slow for PF3 and violent for PCl3, PBr3 and PI3
PCl3 + Cl2 (oxidising agent) —> PCl5
-What is the actual solid state structure of PCl5?
It exists as [PCl4]+[PCl6]-
How does PCl5 react with water and why?
It is hydrolysed because it is lewis acidic
Which is the better base NH3 or PH3 and why?
NH3 because in PH3 there is very little s,p hybridisation therefore the electrons are ion lower energy orbital closer to nucleus and less available for bonding
What is hydrazine, what is it used for?
N2H4 used as rocket fuel, it is a strong reducing agent, thermodynamically unstable.
What is significant about all the oxides of nitrogen?
They’re all thermodynamically unstable (+ve formation enthalpy)
What is produced when NOx is dissolved in atmospheric water?
HNO3 and HNO2 produced
How can NO2 lead to the production of photochemical smog?
NO2 (w/ sunlight) —> NO + O
O2 + O —> O3 - component of photochemical smog
