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  2. Transition metal - Wikipedia

    en.wikipedia.org/wiki/Transition_metal

    The period 6 and 7 transition metals also add core (n − 2)f 14 electrons, which are omitted from the tables below. The p orbitals are almost never filled in free atoms (the one exception being lawrencium due to relativistic effects that become important at such high Z), but they can contribute to the chemical bonding in transition metal ...

  3. HOMO and LUMO - Wikipedia

    en.wikipedia.org/wiki/HOMO_and_LUMO

    Diagram of the HOMO and LUMO of a molecule. Each circle represents an electron in an orbital; when light of a high enough frequency is absorbed by an electron in the HOMO, it jumps to the LUMO. 3D model of the highest occupied molecular orbital in CO 2 3D model of the lowest unoccupied molecular orbital in CO 2

  4. Heteropolymetalate - Wikipedia

    en.wikipedia.org/wiki/Heteropolymetalate

    The metal atoms are usually group 6 (Mo, W) or less commonly group 5 (V, Nb, Ta) transition metals in their highest oxidation states. They are usually colorless to orange, diamagnetic anions. For most heteropolymetalates the W, Mo, or V, is complemented by main group oxyanions phosphate and silicate .

  5. Reactivity series - Wikipedia

    en.wikipedia.org/wiki/Reactivity_series

    The most reactive metals, such as sodium, will react with cold water to produce hydrogen and the metal hydroxide: 2 Na (s) + 2 H 2 O (l) →2 NaOH (aq) + H 2 (g) Metals in the middle of the reactivity series, such as iron , will react with acids such as sulfuric acid (but not water at normal temperatures) to give hydrogen and a metal salt ...

  6. Periodic table - Wikipedia

    en.wikipedia.org/wiki/Periodic_table

    The main-group elements have entirely regular electron configurations; the transition and inner transition elements show twenty irregularities due to the aforementioned competition between subshells close in energy level. For the last ten elements (109–118), experimental data is lacking [79] and therefore calculated configurations have been ...

  7. Valence electron - Wikipedia

    en.wikipedia.org/wiki/Valence_electron

    However, transition elements have (n−1)d energy levels that are very close in energy to the n s level. [2] So as opposed to main-group elements, a valence electron for a transition metal is defined as an electron that resides outside a noble-gas core. [3]

  8. MAX phases - Wikipedia

    en.wikipedia.org/wiki/MAX_phases

    The MAX phases are layered, hexagonal carbides and nitrides which have the general formula: M n+1 AX n, (MAX) where n = 1 to 4, [1] and M is an early transition metal, A is an A-group (mostly IIIA and IVA, or groups 13 and 14) element and X is either carbon and/or nitrogen.

  9. Platinum - Wikipedia

    en.wikipedia.org/wiki/Platinum

    Platinum is a chemical element; it has symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal. Its name originates from Spanish platina, a diminutive of plata "silver". [7] [8] Platinum is a member of the platinum group of elements and group 10 of the periodic table of ...