1 Mr. ShieldsRegents Chemistry U08 L06

2 As we’ve seen, of the 111 named elements 87 are metals. This is about 78% of the periodic table! METALS What defines metallic character? Are some metals more Metallic than others? What determines metallic reactivity?

3 Metals One of the characteristics of metals is that they have A tendency to want to lose electrons (i.e they have low IE) - Will form positive ions - Metals have positive oxidation numbers As we go down a group what happens to IE? IE Decreases And as we go across a period what is the trend for IE? IE Increases

4 Decreasing IE Increasing I.E. Ionization Energy Trends

5 Metals We know that the ease with which a metal loses it’s valence electrons increases with increasing atomic radii Relative Atomic radii Lithium IE = 520 Rubidium IE = 403

6 Metallic Character Since losing electrons is a characteristic of metals How easily a element can lose it’s electron defines METALLIC CHARACTER - i.e The lower the IE the greater the metallic character METALLIC CHARACTER INCREASES GOING DOWN A GROUP AND… METALLIC CHARACTER DECREASES LEFT TO RIGHT ACROSS A ROW (PERIOD)

7 Metallic Character LiBeBCNOF NaMgAlSiPSCl KCa…GaGeAs RbSr CsBa FrRa Decreasing Metallic Character Increasing Metallic Character

8 Metallic Character So if metallic character increases down a group and Decreases across a period what is the most metallic element and what is the least metallic of all elements? Most metallic: Francium Least Metallic of all elements: Fluorine

9 Reaction of K (top) and Ca with water Group 1 Group 2 How can you tell which metal is more reactive? How could you predict one to be more reactive than the other? Metal (2K) + 2H 2 0  H 2 + 2KOH H 2 Gas Reaction Equation for Alkali metals with water: Metal hydroxide

10 Group 1 Metallic Reactivity Lithium is the least reactive Alkali metal Na and K react violently with water; K even more so Than Na. It’s reaction is so exothermic it will ignite the Liberated Hydrogen Rubidium will burst into even if exposed to air The most reactive Alkali metals are Cesium & Francium (the most reactive) Li Na K Rb Cs Fr

11 Potassium will react violently with water Movie: Reaction of Na and Cl 2 (requires Quicktime) These metals will react with many different elements and Compounds. Sodium, less reactive than potassium, still reacts violently with Chlorine.