d block Flashcards
all transition elements forms metal oxides..except one element..who is that
scandium..its is ionic
fajan’s rule
as oxidation state of metal oxides increases,ionic characcter of oxides decreases
condition to form alloy
their radii should be within 15%
ie, should be of similar metallic radii
properties of alloys
*very hot
*high mp
*high resistance to corossion
stainless steel is the alloy of
Fe+Cr+Ni+C
ferrous alloy/steel alloy made up of
Cr,Ni,Mn,V,Mo,W with steel
measuring tape and pendulum are made using
nickel steel
cutting tools and crushing machines are made up of
chrome steel
transition metal ions forms stable complexes due to
*small size
*high charge
*high charge/size (charge density)
*availability of vacant d orbitals
ferric is more stable than ferrrous
[fe(cn)6]^3- > [fe(cn)6]^4-
why?
fe^3+ have high e/m ratio
why interstetial compunds are non stochiometric?
coz the bonding b/w metal atoms and non metal atoms are neither ionic nor covalent
hydride gap
the void of grp 7,8,9 is very small compared to hydride ion(H^-) (2 e,1 p)
hydride ion cant be in these voids.so they cannot form hydride
interstetial compounds are chemically inert.
true/false
true
colourless ions
Fe(3+), Y(3+), Al(3+),Ac(3+),Zn(2+)
a)philosopheres wool/white Zn?
b)white vitreol?
a)Zno
b)ZnSO(4).7H(2)0
amount of energy released during the exhange of electrons of same spin in degenerate orbitals….
exchange energy(exothermic)
pairing energy
amt of energy req to pair up electrons in the same orbital.(endothermic)
haemoglobin is a complex of
Fe2+
german silver is an alloy of
Cu+Zn+Ni
lanthanide contraction relates to atomic radii as well as M(3+) radii
true/false
true
most common oxidation state among lanthanides
+3
Ln(111) compounds are generally colourless.
true/false
false.
most of the trivalent lanthanoid compunds except of La(3+) and Lu(3+) are coloured both in aqueous and solid solution.
lanthanum is grouped with f block elements because
the properties of lanthanum are very similar to 4f series
transition metals present in misch metal
95% rare eartth metals
5% Fe
traces of S,c,Ca,Al
which is the trasition metal as per the ground state?
Au
negligible screening effect of f orbitals are termed as
lanthanoid contraction
the maximum oxidation state exhibited by actinide ions are
+4
actinoid contraction is however greater than lanthanoids.due to
there is poor shielding by 5f electrons
Cr-O-Cr bond angle of dichromate ion ..
179 pm
6 Cr-O bonds in dichromate ion with bond angle
163pm
mixed oxides formed by elements of 3d series of d block is
Cr,Mn,Fe
the difference b/w melting point pf samarium and the upperr value of mp range of lanthanoids is
423.
mp of Sm=1623K;
range:1000-1200K
