periodicity

• how are elements classified in the periodic table?


  s, p, d, f according to which orbitals the highest energy electrons are in
• what happens to the atomic radius as we go across a period?

  decreases

  increased number of protons

  increased positive attraction between nucleus and electron

  more outer electrons in the same shell
• what is the general trend for first ionisation energy?

  increases

  smaller atoms

  increased protons

  increased attraction between nucleus and outer electron
• why does Al have a lower IE than Mg?

  Mg outer electron is in the 3s subshell

  Al outer electron is in the 3p subshell

  Al electron is in a higher subshell therefore electron is easily lost
• why does sulphur have a lower IE than phosphorus?

  sulphurs outer electron is paired in the s orbital (2 electrons)

  electron pair repulsion, electron easily lost

  phosphorus single electron in p orbital