Periodic Table Periodicity - recurrence at regular intervals. Dmitri Medeleev

Periodic Table Dmitri Medeleev It helped predict properties of the missing elements It showed there were missing elements There’s a repeating pattern of properties when the elements are put in order of atomic mass

Periodic Trends Trends within the Periodic Table of Elements Atomic Radii Electronegativity Ionization Energy Density

Periodic Trends Trends within the Periodic Table of Elements Atomic Radii – Size of the atom (e - cloud) Electronegativity – Strength of attracting e - (similar to electron affinity) Ionization Energy – Energy required to remove e - Density – How much mass per volume

Atomic radii in picometers ( m)

37

50

Atomic Radii - Basic Trend: Larger

Electronegativity – The ability of an atom to attract electrons.

Electronegativity - Basic Trend: Larger Electron Affinity – is similar to electronegativity

Ionization Energy – The energy required to remove an electron. First Ionization Energy – The energy required to remove the first electron from a neutral atom. Second Ionization Energy – The energy required to remove the second electron from an atom after its first electron is removed. Third Ionization Energy – The energy required to remove the third electron from an atom...

Relative Trend in FIRST Ionization Energies

Ionization Energy - Basic Trend: Larger

Successive Ionization Energies It ALWAYS gets harder to remove the next electron! There is a tremendous jump in difficulty when the electronic structure is a Noble Gas core!

Density Trend Density = Mass Volume Fun Density Facts: One cm 3 of water has a mass of… grams One cm 3 of gold has a mass of… grams One cm 3 of lead has a mass of… grams 1 cm 3 = about the volume of

Density vs Atomic Number

Density - Basic Trend: Increase

Atomic Radii – Increases down and left. Electronegativity – Increases up and right (H=C) Ionization Energy (First) – Increases up and right. Density – Increases down and to the middle. Review of Trends