p block (n fam) Flashcards
N FAMILY
NITROGEN FAMILY
nitrogen
phosphorous
arsenic
antimony
bismuth
moscovium
this elemnts are known as…..
and its compunds are known as…
pnicogens
pnicanides
moscovium is a synthetic,extremely radioactive,trasactinide element with very short….
half life
nitrogen occur as ……. gas
diatomic
it constitutes ….. % of atmosphere
78
33rd most abundant on earths crust
nitrogen
nitrogen mainly occur as nitrates.Eg
Chile saltpetre- NaNO3
Indian saltpetre - KNO3
essential constituent of protiens,amino acids,nucleic acids
nitrogen
phosphorus is very reactive element hence
it donot occur in free in nature
11 most abundunt in earth crust
phosphorous
phosphorus occur in apetite minerals
3Ca3(PO4)2.CaX2
X=F,Cl,OH
ie, fluroapetite,chloroapetite,hydroxyapetite
As,Sb,Bi are mainly occur as
sulphide minerals
[mispickel,stibnite,realgar,orpiment,bismuth galnce,bismuthinite,bismite]
IE order
N>P>As>Sb>Bi
order of first,second,thrid IE
IE1<IE2<IE3
EN
elecctronegative than grp 14..doen the grp gradual decrease
metallic char
less than corresponding 14th grp..however metallic char increases down the grp
why met.char is less than corresponding 14th
due to increased nuclear charge and higher EN
why met.chr increases down the grp
en decreases down the grp.valence electron are lost more readily.
N & P are non metals
As & Sb are metalloids
Bi typical metal
melting point increases down the grp N to As due to
increase in at.size
why melting point of Sb and Bi decreases
due to inert pair effect,their tendency is to form three covalent bonds instead of 5.this results in weakening of attraction among atoms.
bismuth has weaker interatomic forces than antimony hence melting point
is low
density
increses down the grp
allotropy
exccept N and Bi all have allotropes
phosphorus(3)-red,white,black
As and Sb (2)-yellow,grey
why negative oxdn state
since they have 5 electran as valence only needed3 electrons to attain noble gas configuration.
hence nitrogne forms nitrides (N3-) with highly elecctro[psitive metals(Mg3N2,Ca3N2)
other elements forms coalent compound(Ca3P2,Na3As,Zn3Sb2,Mg3Bi2)
besides -3 ,N and P exhibit -2 oxdn state in…
hydarzine,diphoshpine
N also shows -1 in…….
but phosphorus does not
hydroxylamine
why PF5,PCl5,SbF5 and BiF5 are covalent
due to large amount of energy needed to lose 5 valence electrons,M+5 ions are not formed
but in +3 oxn state these elements forms both ionic and covalent compounds
true
cov char decreases in the order
N>P>As>Sb>Bi
nitrogen because of samll size,high en,strong tendancy to form ppi-ppi multiple bonds shows oxn no. -3 to +5
NH3= -3
NH2NH2= -2
NH2OH= -1
N2= 0
N2O=+1
NO= +2
N2O3= +3
NO2 OR NN2O4= +4
N2O5= +5
max covalency shown by nitrigen due to lone paiir
4
all the oxdn state of nitrogen from +1 to +4 exhibit……. in acidic medium
disproportionation
phosphoru is all oxdn state from -3 to +5 shows
disproportionation in both acidic and basic medium
due to inert pair effecct,the stability of +3 ….. feom As to BBI
increases
melting point orderr of their hydrides
NSAP
N>Sb>As>P
boiling point order of their hydrides
BSNAP
B>Sb>N>A>P
thermal stability
as size increases M-H bond strength decreases,stability decreases
reducing char
increases down the grp
basaic nature
decreases down the grp
hydrides are lewis bases (have a lone pair of electrons on the central atom)
formation of oxides
E2O3,E2O5
how oxn state and oxidic strngth relatedhigher the oxn state of the element greater is its acidic strngth
reactn towards halogens
forms trihalides and pentahalides
why N does not form pentahalides
due to absence of d orbitals
as the size of the halogen grp increases phosphorus-halogen bond strngth decreases due to
steric hindrance
catenation
phosphorus has the max tendency for catenation.
ntrogen has only a little tendency due to N-N single bond is very weak [repulsion of lone pair]
N2 is inert due to
presence of triple bond,bond length is very ssmall.BDE is very small
why nitrogen cant form dpi ppi bonds
absence of d orbitals
nature of trihalides
except nf3 other trihalides of nitrogen unstable and explosive.other trihalides are stable
white phosphorus
discreet units of P4
more reactive
volatile
dissolves in CS2
on contact with air it reats with O2 to give chemiluminesccence
red phosphorus
linear chain of P4
less reactive
less volatile
insoluble in CS2
doesnt give chemiluminiscence
black phos[horus
most thermodynamically stable allotrope
prprn of allotropes
white P when heated with 573K gives red P,its is heated at 803K gives alpha black
otherwise heated at 473 K at high pr. gives beta black
