Adobe Scan Aug 13, 2022
Adobe Scan Aug 13, 2022
Adobe Scan Aug 13, 2022
d- and f- Characteristics of
44 Block Elements
(Transition and Inner-transition
Elements)
d-block Elements: Transition Elements
What are d-Block Elements ?
The definition of d-block elements has already been given in chapter 3
Whny are d-Block Elements Called Transition Elements ?
The d-block elements are called transition elements because they exhibit
transitional behaviour between highly reactive ionic-compound forming s-block
elements (electropositive elements) on one side and mainly covalent-compound
elements (electronegative elements) on the other side)
forming p-block Table.
Position of d-Block Elements in the Periodic
located in between s-(ionic-compound forming elements)
d-block elements are
elements) block elements
as shown in Fig
and p-lcovalent-compound forming table and
a r e located in
the middle of the periodic because
elements
44.1. Thus these of the periodic
table. It is
4) and subsequent periods of
occur in fourth (n elements that the properties
=
d-Block Elements
(Transition Elements
Form covalent
1347
1348
Modern Inorganie Chemistry
Electronic Configurations of d-Block Elements.
omplete and valence-shell
o Zn (Z 30; (6)Y (Z configurations
=
of d-block elements namely la) Se
39) to Cd (Z= 48); (c) La(Z 57),
=
g Z =80); and (d) Ac (Z- 89), KulZ Hf (Z =72) =
groups IlIB, IVB, VB, VIB, VIIB, IB and VIII, elements of the
IIB
belong this block as is evident
rom their
configurations. fi) It may be noted from the valence-shell
of the atoms of
these elements that in the elements like
Cr, Cu, Nb, Mo, Ru,
configurations
Pd, Ag, Pt and Au one or both the
electronsfrom ns orbital get shifted to
Rh,
orbital and hence such elements have one or no electron in ns
orbital
(n-1d
two electrons in ns (instead of
orbital). This type of shifting makes
filled and such (n-1)d orbitals are the
(n-)d orbitals half-filled or
completely
stable than other (n-1)d orbitals. Thus the
shifting
more
orbital to (n-1d orbital gives more stable of one
or both the
from ns electrons
configuration to the atom.
Cassification of d-Block Elements.
Based on whether the differentiating electron goes to 3d, 4d, 5d or 6d
d-block elements have been classified into four series viz. orbitals,
3d, 4d, 5d and 6d series
as discussed in chapter 3.
Atomic volume : 15.0 1.66 8.3 T.2 T.3 7.1 6.7 6.6 7.1 9.2
3.0 4.5
4.5 6.1 7.2 7.4 7.8
(em (glem")3.0 8.9 8.9 8.9 7.1
Density
hracteristacs of d- and f Block
Jhlock elements Elementa
ihe (n-1d
electrons in.
ns
sub-shell is filled 1349
oments compare
hese elements
compared to leads
to the and the
he donsities of d-block those of the comparatively increased nuclear
LA
IA and IA elemen elementa
elements. This is are neighbouring low atomic
and
charg o
volumes
-
very high in p-block
3. Melting and understandable comparison to those elementa
The melting and Boiling Points
because of their of
group
boiling decreasing volumes
given below points of the
elementa of Lst
transition
Elements Sc Ti V
series are
Boiling point Cr Mn Fe Co Ni
rC) 2730 3260 3450 Cu Zn
Melting point 2665 2150 3000
2900 2730 2595 906
rC) 1539 1668 1900
1876 1245 1536
It is evident from the values that 1495 1453 1083 419.5
the d-block elements have high melting and
bouling points. It shows that they are held
the table that the melting and by strong forces. It can be seen
boiling points
the series. In this region the elements havehave highest values in the middle
from
maximum number of
electrons available for bonding. The elements also exhibit the
unpaired
dates in this region. The trend in highest oxidation
melting and boiling points shown by 3d-series
elements is also followed
by 4d and 5d-series elenents. However Zn, Cd and Hg
have relatively low values (melting and boiling points for these metals are
in= 419.5C, 906° C; Cd = 320.9C, 765 C and Hg =-38.4 C, 357C
he reason of these low values is that these metals have completely filled d-orbitals respectively
t h no unpaired electron (Zn = 3d.4s with n = 0, Cd - 4 d 4 with n=0 and
d 6swith n = 0) that may be available for coralent bonding amongst the
ms of these metals and is responsible for high melting and hoiling points
Generally the melting and boiling points of d-block elements increase on
of Ag lower than those of Cu
g a group. Melting and boiling points
are
n
. T h i s can be explained on the basis that both Cu and Au have greater
state than +1, suggesting that in these
t o acquire higher oxidation
for metalie bonding i8 to a greater extent
involvement of d-orbitals
fhans in heAg
h
4. Atomic (Covalent) Radii.
elements are given below
atomic (covalent) radii of d-block
Sc Mn Fe Co Ni Cu
Ti Cr
144 A 1.32 1.22 1.18 1.17 1.17 1.16 1.15 1.17 1.25
Te Ru Rh Pd A Cd
Y Zr Mo
Nb 1.25 1.25 128 1.34 148
A 1.30 1.27
145 1.34
La H W Re Os Ir Pt Au Hg
Ta
88 A 144 1.34
1.30 128 1.26 1.27 1.30 134 149
Positlen d- Block elemends
d-Block alements ase located dn betueen s-
and p- bloCk ecements Thuse
hesa elermonts a Looatad
in e middl the posuiodic table and occuw in fous th
Cn 4) and suhseguent petiods f the peuedic tahle . t
=
valerce-shcl
corqu atien
cer4iguoatisra
from Ch-1)d'. vaitra-sholl
duKE
frn the cunents
hat an d
t
heted
may
be
c6
dTent
and
Au
o r both r b i t a l
ard
aterna Ph br)d
Pd, Ag, w
chiftcd
t e o r b l t a
Ru, Rh, tu
C7,Cu,
Nb, Mo, cvhi
tal. gt chctco
in
half-
ns no
o
fp cra orutals
have
L e u o n s
-Dd ve
e u m e n s
the c r b i t o l e
cuch mtd
arte C-Ud
hfurg
4 and
such
type pld Th
T c e m p a t
mmitals
th-)d
ty str
flt
dran
t a l
0 r e
Classiecatiepgd-8cc alorents
Based en uhsther t s diffeurnaicting caci goes io
Mekallic 0haxactoy
All t e
t7ahstton elemris aE metais. sun ce tha nuimber 4
E ct2e in bz utex mest dall
vey ali, bung g u
Thay ae
haxd, malieaic and dukle
g exhubit all the
3.types q SEucHuaes fatt artr ed Ctuhic (fc),
agenai close packad Chp), and tha
Metaisg vl 418 bedy cerdeved cuhic Cbc),
gveups ak SepeT and more dutile cthan tetur
metals
It
Qppeas that ovalirt and me|allic
bending bete Gist
tn dhe Qfoms ansitien neials The
pesonte uniued d-
CThitals favas pvalent
behdung These metals e
good
Cerciuckor 9 heat 4
ectnicity
2 Aemc veLumes
7he
and densitiCs
alenic voluns and densities
5ene ad seies
elerarts givn y
SC 15
7-2 7-2
Mh 73 74
In d-bltdk
dernent s Ch-) d Subshel es filied ad te
UnCTecsed huucihay chage the ce cEEh 4n Thu lnads to
#e Cempasatively Jcu aiomic
1o bese y the
vetunes Casc cltints CBmpaed
the
haighbeunng S- and P- blek camintS
dunsities f d-bock denints Ee
40 tese voy high an
grop 1 h4 1A ernarts Cempavsio
becaiuse Tha s
thir deceasurg elume destan dable
Melking and BRlug pelrts
7he meltug ana bcug peits oy da Clerernts 0@
Shewn MMe
a730 1539
TI 60 bb8
C 2k5 (8 76
t 1s evidont fem t e vales d t the d- bleck dlrerts
ty hucteus
Te Lt thds to educe tha SuZe Ht the same tin the
addi ten 4Cca CLetaesto the 3d orht Lal also provids
a Stocening eifect whuch shieids B 4s-Clucbens f7em thu
tnunsct pull e the pestbive hucluus Gn hese elettaons Thss
SCreenig ohfcct increases as thu nunber g extia olecichs
being adlded to ad-07bital increass 7hs eHect oPpestsha Ure
Uh size Thus tero ase pexatig tuo effots rnoly soecning
ejectand hucteax Chnge efggt ühth epp0ses eath Gthu
a e voy shight Vasuiations in the attmlc radius fen Cr to Cu
QHe BAseved
In a paxdiculax soics the atomio uacics ctaire o
V ad incgonses
munurnum value for te elonerts gacup
end of a soLlOS
agan touaxds t
Tohic Radii
The onic socii fUllow te sane trord as the atornic
the
Tt may be seon h a t #e iadii y he dens having
hd in atomic
Same chaHge Cvalency)dec7ease with dhe ucrease
rLurnbor
Tohisatieh Potentats
Tha ierisntien potenbial valuos y mogt ef the d-block
Clements Lies in betwcon these f and p- bleCk elorTorts
This rrintes that dhe d bleck elerertscoe less eloctrepestttve
than s-blck elernonis and rove o than p-block elernents
Thus d-block ekements do net fom iohic compeulndls s0
6aacly os tho alkall and alialine casth matals do Unute s- block
humbet
I h gelng down a greup, The highes oxiclation States becoma
Fe axe
ore Stable oy
e9 1 and 13 Cxidatieh States ghcun ly
Ctoble Bkicotten stateS uhile t4 th ast wnstadle Cta
Tha elative Stabiuity vasiods Oridaten States 4a
on tha bosLs thz Seabil ty Y
gwon elument on be explaind
more
dO,d
5 and do onfiquxation fy og M ( 2d 0,45°) t3
the Prcgonte y 3a Drbtal
Ctable than Ti (ad' 43) because
In Ti 10h.
luc
THansiteh elamrts
bends un thuis
aan fom dehlc
Nomaliy
the onpeunds y s-4 p-hlock o 7
thu olua
ctodess u h tose anitton rnetals un
ottukcon State aa usually celae
PHamgnebism
Diamaqnetism
Feromagnatism
RHamagnetisn
This ptopecty B Soun by the Suhstanas uhich, when
placed betu/eon he nagnutic psits alow tbe hagretic lihes
y fooce 0 m g h than stifhey ban h0ugh vac tuum e
a poxamagretic kar wie terd to se Lsolf with its longth pevallel
Ramagretion
his pepesty B ekhbited hy Je substanes uhich alpw
tha vacuum ratex
hs magretc lires fovce dte pass Bmeugh
then reugh themacLves ThLS a auunag/atíc substana is Tepclled
by a
mag hetic ficld, and heno utends bo CE Eself at righMt
the eectren paired
angles flcd The 0ompolds aving all
to do
tonaten Alleys
with eath otar, this
Tsaneition metats fom alloys
B because they have Qlmest sim lay Sizes and the atems
cne metal can easily take up poitlsra un the crystal
Jattio the stter. Thuus we have alap -Ni,
Mnfe ctc. Auloys au usuaby hasides and have highe
metting peurt than he pasvert metals They a more
esistant to cOTodieD than tuir cestituents
VANARILMPENTOKLDE
Faxegacish ammerium
metasanadate,
/
duced uith k, hypovanadum
elbtained
VaOgt6K VaO t aK,0
vaadiunm ioicde
w Va0, uduad by H or sulphur,
CVa0a) is ebtainad
Vay+2H
A V 0 g t 2H0
As Sg t
10 HNOg 2HgAs04+ lONOt 24h0 + E