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  2. Periodic trends - Wikipedia

    en.wikipedia.org/wiki/Periodic_trends

    Trend-wise, as one moves from left to right across a period in the modern periodic table, the electronegativity increases as the nuclear charge increases and the atomic size decreases. However, if one moves down in a group , the electronegativity decreases as atomic size increases due to the addition of a valence shell , thereby decreasing the ...

  3. Electronegativity - Wikipedia

    en.wikipedia.org/wiki/Electronegativity

    In general, electronegativity increases on passing from left to right along a period and decreases on descending a group. Hence, fluorine is the most electronegative of the elements (not counting noble gases ), whereas caesium is the least electronegative, at least of those elements for which substantial data is available.

  4. Lanthanide contraction - Wikipedia

    en.wikipedia.org/wiki/Lanthanide_contraction

    The lanthanide contraction is the greater-than-expected decrease in atomic radii and ionic radii of the elements in the lanthanide series, from left to right. It is caused by the poor shielding effect of nuclear charge by the 4f electrons along with the expected periodic trend of increasing electronegativity and nuclear charge on moving from left to right.

  5. Actinide contraction - Wikipedia

    en.wikipedia.org/wiki/Actinide_contraction

    It is more pronounced than the lanthanide contraction because the 5f electrons are less effective at shielding than 4f electrons. [1] It is caused by the poor shielding effect of nuclear charge by the 5f electrons along with the expected periodic trend of increasing electronegativity and nuclear charge on moving from left to right.

  6. Electron affinity - Wikipedia

    en.wikipedia.org/wiki/Electron_affinity

    Counterintuitively, E ea does not decrease when progressing down most columns of the periodic table. For example, E ea actually increases consistently on descending the column for the group 2 data. Thus, electron affinity follows the same "left-right" trend as electronegativity, but not the "up-down" trend. The following data are quoted in kJ/mol.

  7. Post-transition metal - Wikipedia

    en.wikipedia.org/wiki/Post-transition_metal

    The diminished metallic nature of the post-transition metals is largely attributable to the increase in nuclear charge going across the periodic table, from left to right. [8] The increase in nuclear charge is partially offset by an increasing number of electrons but as these are spatially distributed each extra electron does not fully screen ...

  8. Ionization energy - Wikipedia

    en.wikipedia.org/wiki/Ionization_energy

    Ionization energy trends plotted against the atomic number, in units eV.The ionization energy gradually increases from the alkali metals to the noble gases.The maximum ionization energy also decreases from the first to the last row in a given column, due to the increasing distance of the valence electron shell from the nucleus.

  9. Periodic table - Wikipedia

    en.wikipedia.org/wiki/Periodic_table

    Metallic character increases going down a group and from right to left across a period. Nonmetallic character increases going from the bottom left of the periodic table to the top right. The first periodic table to become generally accepted was that of the Russian chemist Dmitri Mendeleev in 1869; he formulated the periodic law as a dependence ...