11Mr. Shields Regents Chemistry U08 L06

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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 moreMetallic than others? What determines metallic reactivity?

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MetalsMetalsOne 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

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Decreasing IE

Increasing I.E.

Ionization Energy Trends

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MetalsMetalsWe know that the ease with which a metal loses it’s valence electrons increases with increasing atomic radii

Relative Atomic radiiLithium IE = 520

Rubidium IE = 403

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Metallic CharacterMetallic CharacterSince losing electrons is a characteristic of metals

How easily a element can lose it’s electron definesMETALLIC CHARACTER

- i.e The lower the IE the greater the metallic character

METALLIC CHARACTER INCREASES GOING DOWNA GROUP AND…

METALLIC CHARACTER DECREASES LEFT TO RIGHTACROSS A ROW (PERIOD)

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Metallic CharacterMetallic Character

Li Be B C N O F

Na Mg Al Si P S Cl

K Ca… Ga Ge As

Rb Sr

Cs Ba

Fr Ra

Decreasing Metallic CharacterIn

crea

sing

Met

allic

Cha

ract

er

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Metallic CharacterMetallic CharacterSo if metallic character increases down a group andDecreases across a period what is the most metallicelement and what is the least metallic of all elements?

Most metallic: Francium

Least Metallic of all elements: Fluorine

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Reaction of K (top) and Ca with water

Group 1

Group 2How can you tell which metalis more reactive?

How could you predict one tobe more reactive than theother?

Metal (2K) + 2H20 H2 + 2KOH

H2 Gas

Reaction Equation forAlkali metals with water:

Metal hydroxide

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Group 1 Metallic ReactivityGroup 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 theLiberated Hydrogen

Rubidium will burst into even if exposed to air

The most reactive Alkali metals areCesium & Francium (the most reactive)

Li

NaK

Rb

CsFr

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Potassium will react violently with water

http://jchemed.chem.wisc.edu/JCESoft/CCA/CCA0/MOVIES/NACL1.htmlMovie: Reaction of Na and Cl2 (requires Quicktime)

These metals will react with many different elements and Compounds. Sodium, less reactive than potassium,still reacts violently with Chlorine.