periodicity

• general trend across a period

  as you go across typically IE increases due to

  • increased NC=increased NA so more energy required to remove one e-
  • AR decreases=increased NA so more energy required to remove one e-
  • ES stays relatively the same so no effect on IE
• anomalies across a period

  group 2-3

  the electron removed from group2 element is from S orbital, the electron removed from group3 element is from P orbital which is higher energy state

  group 5-6

  the electron removed from group5 element is unpaired electron from P orbital, the electron removed from group6 orbital is paired electron frkm P orbital. paired are in higher energy state
• general trend down a period typically IR decreases due to

  • AR increases = NA decreases so less energy required to remove electron
  • ES increases = NA decreases so less energy required to remove electron
  • NC increases = NA increases but other two factors outweigh so IE decreases