Periodic Table Trends

Electronegativity (electron affinity) Periodic Table Trends Atomic Size/Radius Ionization Energy Electronegativity (electron affinity)

Atomic Radius (size) How large an atom is

Atomic Radius (notice any patterns?)

Atomic Size/ Atomic radius down groups  Increases Electrons in increased energy levels (shells) across periods  Decreases. There are more valence electrons in the same shell (energy level) so they pull towards the nucleus which has an increased number of protons. More number of protons in the nucleus- more proton pulling power

Ionization Energy Energy required to remove one electron from an atom in the gas phase.

Ions When an element loses an electron it forms a positively charged ion called cation

Ions When an element gains an electron it forms a negatively charged particle called anion.

Ionization Energies (notice any patterns?)

Ionization Energies (notice any patterns?)

Ionization Energy Down groups  Decreases Across periods  increases as electrons are further from the nucleus there is lesser pull from protons Across periods  increases Electrons are added to the same energy level, so proton pulling power on electrons is higher.

Do Now Which atom in each pair has the larger atomic radius and Ionization energy? Li or K Ca or Ni Ga or B O or C Cl or Br f) Be or Ba

Electronegativity- Measure of how strongly an atom attracts a bonding pair of electrons to itself

Trend for electronegativity

Trends in Electronegativity: down groups  decreases The electrons are further from the nucleus, so less pulling from protons across periods  increases as atoms have more valence electrons in the same energy level and more protons in nucleus they have a higher pulling power.

Practice Problems 1. Which of the following elements has the smallest ionization energy; Sodium, Calcium, Potassium, Magnesium 2. List the following elements in increasing ionization energy (smallest to largest) Cesium, Bismuth, Oxygen, Beryllium 3. List the following elements in the increasing order of electro negativity Chlorine, Flourine, Carbon, Magnesium