Elements

• periodic table of the elements
  • periodic trends

Classification

• halogens
• noble gases (גזים אצילים)
• metallic classification
  • metals
    • alkali metals (מתכות אלקליות)
    • alkaline earth metals (מתכות אלקליות-עפרוריות)
    • transition metals (or transition elements)
      • inner transition metals
  • metalloids (מתכות למחצה)
  • nonmetals (אל-מתכות)
• other classifications
  • main-group elements (or representative elements)

Properties

• [[Mass#of-an-element|atomic mass]] (see also molar mass)
• physical properties:
  • melting point (at a given pressure)
  • boiling point (at a given pressure)
  • heat of fusion
  • heat of vaporization
  • molar heat capacity
  • specific heat capacity
  • vapor pressure (at a given temp.)
• atomic properties:
  • oxidation states of element
  • ionization energies (1st, 2nd, …)
  • electron affinity
  • electronegativity $\chi$
    • “the tendency for an atom of a given chemical element to attract shared electrons (or electron density) when forming a chemical bond” (Wikipedia)
    • Follows a similar trend to electron affinity
    • Increases from bottom left to top right of the periodic table
    • Pauling scale
  • Atomic radius
  • effective nuclear charge ($Z_{\text{eff}}$)
    • $Z_{\mathrm{eff}}=Z-S$
    • $Z$ is the atomic number (number of protons)
    • $S$ is the shielding constant
      • It represents the portion of the nuclear charge that is screened from a valence electron by the other electrons in the atom.
      • Because core electrons are most effective at screening a valence electron from the nucleus, the value of $S$ is usually close to the number of core electrons
• other properties:
  • thermal conductivity
  • electrical resistivity