Periodic Trends (IE, EA, AR and ENC)

• Effective nuclear charge - Z = charge of the nucleus (protons)
• Effective nuclear charge - Z(eff)= effective nuclear charge, magnitude of positive charge "experienced" by an e- in an atom.
• Effective nuclear charge - H atom = ONLY atom when the nuclear charge = effective nuclear charge
• Effective nuclear charge - Shielding = electrons are partially shielded from the positive charge of the nucleus including fellow electrons
• Effective nuclear charge - effective shielders = CORE electrons

  • Shields more
  • INCREASES ENC, left to right across PT
  • # of core electrons are the same
  • INCREASES in Z and valance electrons
• Atomic Radius - Distance between the nucleus and valance shell

  • Going DOWN a group, radius INCREASES
  • due to atomic shells, n, INCREASING
• Atomic Radius - Metallic Radius = 1/2 distance between nuclei of two adj. metal atoms
• Atomic Radius - Covalent Radius = 1/2 distance between nuclei of two adj. atoms connected by a chemical bond
• Atomic Radius - size INCREASES as you go down the group.

  • INCREASES in shells of e- = LARGER
• Atomic Radius - size DECREASES as you go left to right a period.

  • ENC INCREASES, pulling e- closer
  • Subshells puts e- into inner shells
  • As e- is added to the outermost shells = DECREASE in attractive force
• Ionization Energy - minimum energy required to move 1 e- from a gaseous atom/ion in the ground state. (kJ/mol^-1)
• Ionization Energy - Formula: Energy x Avogadro's #(kJ/mol-1)