Actinides vs Lanthanides
Lanthanides and actinides are separately shown in two rows in the periodic table. They both belong to the f block.
Actinide is a set of elements in the periodic table with the atomic numbers ranging from 90 to 103. There are 14 metal elements. They are thorium Th (Z=90), protactinium Pa (91), uranium U (92), neptunium Np (93), plutonium Pu (94), Americium Am (95), curium Cm (96), berkelium Bk (97), californium Cf (98), einsteinium Es (99), fermium Fm (100), mendelevium Md (101), a unit Ї 102, and lawrencium Lr (103). These are f block elements; because their final electrons are filled into an f sub orbital. All the actinides are unstable; therefore, all are radioactive. Since they are metals, they are highly electropositive. They are dense metals, and numerous allotropes are present. These metals readily tarnish in the air and react with boiling water or dilute acid releasing hydrogen gas. As other metals, they can also form compounds with nonmetal elements. Actinides are found in the natural environment, though some are very rare. Uranium and thorium are present as deposits, in Canada. Due to their radioactivity, most of the actinides are used for nuclear energy production. Actinide elements are produced synthetically for use of various purposes. Other than that some of them are used for medicinal purposes, mineral identification, neutron radiography, etc.
Lanthanides contain elements from atomic number 57 to 71. There are 15 metallic elements as lanthanum La (57), cerium Ce (58), Praseodymium Pr (59), neodymium Nd (60), promethium Pm (61), samarium Sm (62), Europium Eu (63), Gadolinium Gd (64), Terbium Tb (65), dysprosium Dy (66), Holmium Ho (67), yttrium Er (68), thulium Tm (69), ytterbium Yb (70), and Lutetium Lu (71). These belong to the f block in the periodic table; hence final electrons are filled into the 4f sub orbital. The 4f orbitals are buried inside other sub orbitals, and the chemistry of lanthanides differ due to the size of the atom. They show +3 oxidation state. From left to right of a row in the periodic table, the size of +3 lanthanide ions decreases, and this is known as lanthanide contraction. Lanthanides are silver color metals, which react readily with oxygen in the air to produce their oxides. Lanthanides are highly reactive, relatively soft metals with high melting points and boiling points. They readily form ionic compounds with non metals. When reacting with dilute acid or water lanthanides produce hydrogen gas. Lanthanides have unpaired electrons (except lutetium), which are responsible for their paramagnetic properties. Lanthanides are also known as rare earth metals due to the low abundance in earth surface. Although they are rare, there are lots of usages from these elements. They are used as catalysts in glass production, petroleum, etc. Further they are used in magnets, phosphors, lamps, superconductors, optoelectronic applications, etc.
What is the difference between Actinides and Lanthanides?
• Actinides fill electrons to 5f sub orbitals, whereas lanthanides fill electrons up to 4f sub orbitals.
• All the actinides are radioactive, but lanthanides are not (except promethium).
• Lanthanides show maximum oxidation state +4 where as actinides show +3, +4, +5, +6 and +7 oxidation states.