Group 3 element

The elements in this group have three electrons in their outer-most electronic shell. The electronic configurations of the n th orbitals (i.e. outer-most orbitals) are ns2 np1. Thus, each element in this group has a tendency to lose three electron, to form a triply charged positive ion, which has the stable electronic configuration of its nearest neighbouring Nobel Gas element in the periodic table. The elements in the group arechemically reactive.

• IUPAC has not recommended a specific format for the periodic table, so different conventions are permitted and are often used for group 3. The following d-block transition metals are always considered members of group 3: • scandium (Sc) • yttrium (Y) • When defining the remainder of group 3, four different conventions may be encountered: • Some tables include lanthanum (La) and actinium (Ac), (thebeginnings of the lanthanide and actinide series of elements, respectively) as the remaining members of group 3. In their most commonly encountered tripositive ion forms, these elements do not possess any partially filled f orbitals thus resulting in more d-block-like behavior.

• Some tables include lutetium (Lu) and lawrencium (Lr) as the remaining members of group 3. These elements terminate the lanthanide and actinide series, respectively. Since the f-shell is nominally full in the ground state electron configuration for both of these metals, they behave most like d-block metals out of all the lanthanides and actinides, and thus exhibit the most similarities in properties with Sc and Y. For Lr, this behavior is expected, but it has not been observed because sufficient quantities are not available. • Sub-Group IIIa : Transition Metal ElementsScandium Yttrium Lanthanum • The following elements also have the same electronic configuration as lanthanum (i.e. 4s2 4p1) in their outer-most electronic orbitals, while the inner 3d orbitals are being filled, from going from element to element.

• Cerium Praeseodymium Neodymium Promethium SamariumEuropium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutecium These are the transition elements, and are also called the Lanthanides .

• Actinides. The following elements also have the same electronic configuration as actinium (i.e. 5s2 5p1) in their outer-most electronic orbitals, while the inner 4d orbitals are being filled, on going from element to element. • Neptunium Plutonium Americium Curium Berkelium These are the inner transition elements, and are also called the Actinides.

Sub-Group IIIb : Main Group Elements

• Boron Aluminium Gallium Indium Thallium

Lanthanides

• The term rare earth elements is often used for group 3 elements including the lanthanides but excluding the actinides Occurrence

• Scandium, yttrium, and the lanthanides (except promethium) tend to occur together in the Earth's crust, and are relatively abundant compared with most d- block metals, but often harder to extract from their ores. • Biological chemistry. Group 3 elements are generallyhard metals with low aqueous solubility, and have low availability to the biosphere. No group 3 has any documented biological role in living organisms. The radioactivity of the actinides generally makes them highly toxic to living cells.

lanthanide • Lanthanum is a chemical element with the symbol La and atomic number 57. Lanthanum is a silvery white metallic elementthat belongs to group 3 of the periodic table and is a lanthanide. It is found in some rare-earth minerals, usually in combination with cerium and other rare earth elements. Lanthanum is a malleable, ductile, and soft metal that oxidizes rapidly when exposed to air. It is produced from the minerals monazite and bastnäsite using a complex multistage extraction process. Lanthanum compounds have numerous applications as catalysts, additives in glass, carbon lighting for studio lightingand projection, ignition elements in lighters and torches, electron cathodes, scintillators, and others. Lanthanum carbonate (La2(CO3)3) was approved as a medication against renal failure.

Properties

• Physical Properties. • Lanthanum is a soft, malleable, silvery white metal which has hexagonal crystal structure at room temperature. At 310 °C, lanthanum changes to aface- centered cubic structure, and at 865 °C into a body-centered cubic structure Lanthanum easily oxidizes (a centimeter-sized sample will completely oxidize within a year) and is therefore used as in elemental form only for research purposes. For example, single La atoms have been isolated by implanting them into fullerene molecules. If carbon nanotubes are filled with those lanthanum-encapsulated fullerenes and annealed, metallic nanochains of lanthanum areproduced inside carbon nanotubes. •

Chemical Properties

• Lanthanum exhibits two oxidation states, +3 and +2, the former being much more stable. For example, LaH3 is more stable

than LaH2. Lanthanum burns readily at 150 °C to form lanthanum(III) oxide: 4 La + 3 O2 → 2 La2O3 • However, when exposed to moistair at room temperature, it forms a hydrated oxide with a large volume increase.[ • Lanthanum is quite electropositive and reacts slowly with cold water and quite quickly with hot water to form lanthanum hydroxide: • 2 La (s) + 6 H2O (l) → 2 La(OH)3 (aq) + 3 H2 (g)

• Lanthanum metal reacts with all the halogens. The reaction is vigorous if conducted at above 200 °C: 2 La (s) + 3 F2 (g) → 2 LaF3 (s) • 2 La (s) + 3 Cl2 (g) → 2 LaCl3 (s) • 2 La (s) + 3 Br2 (g) → 2 LaBr3 (s) • 2 La (s) + 3 I2 (g) → 2 LaI3 (s) • Lanthanum dissolves readily in dilute sulfuric acid to form solutions containing the La(III) 3+ ions, which exist as [La(OH2)9] complexes: • 2 La(s) + 3 H2SO4 (aq) → 2 3+ La (aq) + 3 SO2−4 (aq) + 3 H2 (g). • Lanthanum combines with nitrogen, carbon, sulfur, phosphorus, boron, selenium, silicon and arsenic at elevated temperatures, forming binarycompounds.

Production

Lanthanum is most commonly obtained from monazite and bastnäsite. The mineral mixtures are crushed and ground. Monazite, because of its magnetic properties, can be separated by repeated electromagnetic separation. After separation, it is treated with hot concentrated sulfuric acid toproduce water-soluble sulfates of rare earths. The acidic filtrates are partially neutralized with sodium hydroxide to pH 3-4. Thorium precipitates out of solution as hydroxide and is removed. After that, the solution is treated with ammonium oxalate to convert rare earths to their insoluble oxalates. The oxalates are converted to oxides by annealing. The oxides are dissolved in nitric acid that excludes one of the main components, cerium, whose oxide is insoluble in

HNO3.

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