The Inner Transition Metals

1A 2A 3A 4A 5A 6A 7A 8A
(1) (2) (13) (14) (15) (16) (17) (18)
3B 4B 5B 6B 7B — 8B — 1B 2B
(3) (4) (5) (6) (7) (8) (9) (10) (11) (12)
1 H He
2 Li Be B C N O F Ne
3 Na Mg Al Si P S Cl Ar
4 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
5 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe
6 Cs Ba La   Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
7 Fr Ra Ac   Rf Db Sg Bh Hs Mt Ds Rg Uub — Uuq — — — —
6   Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
7   Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

 

The inner transition elements occupy a position in between the elements lanthanum (Z=57) and hafnium (Z=72), and between actinium (Z=89) and rutherfordium (Z=104).  Elements 58-71, which follow lanthanum, are the lanthanides, and elements 90-103, which follow actinium, are the actinides.  There is actually some question as to whether lanthanum and actinium should be considered as part of the transition metal group 3B, with the elements following them as being the lanthanides and actinides respectively, or whether lanthanum and actinium should be considered the first elements of the lanthanides and actinides, with lutetium and lawrencium being a part of Group 3B.  The arrangement shown above is move traditional, but there seems to be a growing trend to favor the latter scheme.

In order to compact the periodic table, the lanthanides and actinides are often shown as a separate little "island" underneath the main body of the table (analogous to maps of the United States which show Alaska and Hawaii floating off the coast of California).  For a look at the periodic table with these elements incorporate into the main table, see here.

The inner transition elements are sometimes called the f-block elements, since in this region the f-orbitals are being filled in.

The lanthanides (except for the synthetic element promethium), along with scandium (Sc) and yttrium (Y) are sometimes referred to as "rare earth elements" or "rare earth metals" (or just "rare earths").  This term is not used much anymore, in part because of the ambiguity of which elements "should" be included in this category, and also because many of these "rare" elements are not especially rare.  Cerium is the 25th most abundant element in the Earth's crust, and even the least abundant of the naturally-occurring lanthanides, lutetium, the 60th most abundant element, is much more common than either silver or gold.

The period 6 inner transition metals (lanthanides) are cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu).  The period 7 inner transition metals (actinides) are thorium (Th), protactinium (Pa), uranium (U), neptunium (Np), plutonium (Pu), americium (Am), curium (Cm), berkelium (Bk), californium (Cf), einsteinium (Es), fermium (Fm), mendelevium (Md), nobelium (No), and lawrencium (Lr).

 

 

References

John Emsley, The Elements, 3rd edition.  Oxford:  Clarendon Press, 1998.

John Emsley, Nature's Building Blocks:  An Z-Z Guide to the Elements.  Oxford:  Oxford University Press, 2001.

David L. Heiserman, Exploring Chemical Elements and their Compounds.  New York:  TAB Books, 1992.