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  2. Transition metal - Wikipedia

    en.wikipedia.org/wiki/Transition_metal

    Late transition metals are on the right side of the d-block, from group 8 to 11 (or 12, if they are counted as transition metals). In an alternative three-way scheme, groups 3, 4, and 5 are classified as early transition metals, 6, 7, and 8 are classified as middle transition metals, and 9, 10, and 11 (and sometimes group 12) are classified as ...

  3. Atomic electron transition - Wikipedia

    en.wikipedia.org/wiki/Atomic_electron_transition

    The energy of an electron is determined by its orbit around the atom, The n = 0 orbit, commonly referred to as the ground state, has the lowest energy of all states in the system. In atomic physics and chemistry , an atomic electron transition (also called an atomic transition, quantum jump, or quantum leap) is an electron changing from one ...

  4. Technetium - Wikipedia

    en.wikipedia.org/wiki/Technetium

    Technetium halides exhibit different structure types, such as molecular octahedral complexes, extended chains, layered sheets, and metal clusters arranged in a three-dimensional network. [50] [51] These compounds are produced by combining the metal and halogen or by less direct reactions. TcCl 4 is obtained by chlorination of Tc metal or Tc 2 O 7.

  5. Americium - Wikipedia

    en.wikipedia.org/wiki/Americium

    Americium is a synthetic chemical element; it has symbol Am and atomic number 95. It is radioactive and a transuranic member of the actinide series in the periodic table, located under the lanthanide element europium and was thus named after the Americas by analogy.

  6. Periodic table - Wikipedia

    en.wikipedia.org/wiki/Periodic_table

    The 2s electron is lithium's only valence electron, as the 1s subshell is now too tightly bound to the nucleus to participate in chemical bonding to other atoms: such a shell is called a "core shell". The 1s subshell is a core shell for all elements from lithium onward. The 2s subshell is completed by the next element beryllium (1s 2 2s 2). The ...

  7. Electron configurations of the elements (data page) - Wikipedia

    en.wikipedia.org/wiki/Electron_configurations_of...

    This page shows the electron configurations of the neutral gaseous atoms in their ground states. For each atom the subshells are given first in concise form, then with all subshells written out, followed by the number of electrons per shell. For phosphorus (element 15) as an example, the concise form is [Ne] 3s 2 3p 3.

  8. Electron configuration - Wikipedia

    en.wikipedia.org/wiki/Electron_configuration

    The naïve application of the aufbau principle leads to a well-known paradox (or apparent paradox) in the basic chemistry of the transition metals. Potassium and calcium appear in the periodic table before the transition metals, and have electron configurations [Ar] 4s 1 and [Ar] 4s 2 respectively, i.e. the 4s-orbital is filled before the 3d ...

  9. d electron count - Wikipedia

    en.wikipedia.org/wiki/D_electron_count

    The d electron count or number of d electrons is a chemistry formalism used to describe the electron configuration of the valence electrons of a transition metal center in a coordination complex. [ 1 ] [ 2 ] The d electron count is an effective way to understand the geometry and reactivity of transition metal complexes.