The Periodic Table

I will know….. × What is a periodic table and why is it important. × What are the Parts of the periodic table. × Groups × Periods × Blocks × What are some trends on the periodic table. (atomic size, metallic nature, electronegativity and ionization energy) × Group Properties – Grp. I (1), VII (17), VIII (18) and Transition Elements

What is a periodic table?  It is the most important tool of chemistry.  The periodic table is a tabular arrangement of the chemical elements by increasing atomic number  It has 18 groups and 7 periods and 4 blocks.  Group number = valence electrons  Period number = # of principal energy shells  What does a block denote? (research question)

Why is the periodic table important?  It provides an extremely useful framework to 1. Classify 2. Systematize 3. Compare different forms of chemical behavior. 4. Predict properties of unknown elements based on their position on the periodic table.

Group – represents number of valence electrons  Vertical columns, also called families or groups  The following names for specific groups in the periodic table are in common use:  Group 1: alkali metals -  Group 2: alkaline earth metals  Group 3- 12: Transition elements  Group 11: coinage metals (not IUPAC approved name)  Group 15: pnictogens (not IUPAC approved name)  Group 16: Chalcogens  Group 17: halogens -  Group 18: noble gases/inert -

Period - represents number of principal energy shells  Horizontal rows  First period - shortest  Sixth period - longest

Block  A block of the periodic table of elements is a set of adjacent groups. The term appears to have been first used by Charles Janet.  These blocks are s-block, p- block, d-block, and f-block.

How Does The Organization Of Elements In The Periodic Table Help Us To Make Predictions? Group properties and Periodic Trends

Some Periodic Properties PropertySimple Definition Atomic RadiusSize of atom Ionization EnergyEnergy required to lose a valence electrons Electron Affinity Energy required to gain a single electron ElectronegativityEnergy required to attract a bond pair of electrons

Periodic Trends Property Trend in a Group Reason Trend in a Period Reason Atomic Radius Increases on going down a group An extra shell is added Decreases across a period Effective nuclear charge increases Ionization Energy Decrease on going down a group Large size Increases across a period Small size Electron Affinity Increase down a group Large size Decrease across a period Small size Electronegativ ity Decrease on going down a group Large size Increases across a period Small size

Summary of Trends in the Periodic table