Inner transition elements are those in which f-orbitals are progressively filled. In lanthanoids 4f-orbitals and in actinides 5f-orbitals are filled up. All the elements in f-block are metals and they are also called inner transition elements. The elements of the two series at the bottom of the periodic table together form the f-block elements. The atoms of f-block elements have their last three shells incompletely filled. The f-block consists of thirty elements.
In the elements of the sixth and seventh periods, f sub shell orbitals exist and can be filled. The elements for which f sub shells are filling are sometimes called the inner transition elements or most usually lanthanides and actinides. The lanthanides start with lanthanum which has the electron configuration [Xe] 5d6s2.
Inner Transition Metals DefinitionBack to Top
The two rows of elements at the bottom of the periodic table are called inner transition elements. The first row is referred to as the lanthanides the second row as the actinides. Some of the inner transition elements are synthetic not found in nature.
Periodic Table Inner Transition MetalsBack to Top
The two series are called lanthanides that have atomic atomic number from 57 to 71 and actinides having atomic numbers from 89 to 103. The series actinides contains some synthetic elements that do not occur in nature but are prepared in the laboratories. These synthetic elements exist for a brief period of time.
The atoms of inner transition elements have their outermost three shells incompletely filled. The inner transition elements form the f-block elements.
Inner Transition Metals ListBack to Top
|9 ||Dysprosium ||Dy |
|10 ||Holmium ||Ho |
|11 ||Erbium ||Er |
|12 ||Thulium ||Tm |
|13 ||Ytterbium ||Yb |
|14||Lutetium ||Lu |
List of inner transition elements actinides are given below.
|10 ||Einsteinium||Es |
|11 ||Fermium ||Fm |
|12 ||Mendelevium ||Md |
|14 ||Lawrencium ||Lr |
Inner Transition Metals PropertiesBack to Top
1. Electronic configuration
The electronic configuration if the lanthanides is (6-2)f1-14(6-1)d0-16s2. Lanthanides series begins at cerium (Z=58) and ends at lutetium (Z=71). Similarly the electronic configuration of actinides is (7-2)f1-14(7-1)d0-17s2. Actinides series begins at thorium (Z=90) and ends at lawrencium (Z=103).
2. Oxidation states
The main oxidation state exhibited by all the lanthanides is +3. Some elements also show +2 and +4states but +3 is more stable. Actinides shoe the common oxidation states of +2, +3, +4, +5 and +6.Most common is the +3 oxidation state.
Most of the compounds are colored in both solid as well as in aqueous solution.
- Colorless - La, Ce, Lu, Yb, Gd
- Green - Pr, Tm
- Pale pink - Eu, Tb
- Pink - Er, Nd
- Yellow - Sm, Dy
4. Magnetic properties
The elements are paramagnetic in nature as they have unpaired electrons.
La, Lu and Ce have no unpaired electron so they are diamagnetic in nature.
5. Chemical reactivity
All the elements have almost same reactivity due to the fact that 4f electrons in lanthanides are very effectively shielded from the interaction with other elements by overlapping 5s, 5p, 6s electrons. Due to their similar nature of reactivity they occur together and their separation is difficult.
Transition ElementsBack to Top
The transition elements show some well defined horizontal similarities in physical and chemical properties in contrast the s and p block elements as well as typical vertical group relationship.
The second series is known as actinide series (5f). Like the lanthanides this series also comprises fourteen elements and is placed in the seventh period in the periodic table.