1 ENGAGE: The Element Song 1955 Click above!

2 Patterns and Trends

The Group Numbers on top for columns of “families.” Group numbers are also related to the number of valence electrons. This is group 1 the alkali group. Families have similar but not identical characteristics Increasing Atomic mass going down a group

Periods numbered down the side and form rows or “periods.” This is period number 3 which means it has 3 energy levels. This is period number 3 which means it has 3 energy levels. Increasing Atomic mass going across a period.

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6 Consider a simple diatomic molecule. The distance between the two nuclei is called the bond distance. If the two atoms which make up the molecule are the same, then half the bond distance is called the covalent radius of the atom. Sizes of Atoms and Ions

7 Periodic Trends in Atomic Radii down a group, the atoms become larger. across a period, atoms become smaller. Larger radius

8 Energy Level 3: Na, Mg, Al, Si, P, S Cl & Ar Periods represent the number of rings or what scientists call “energy levels” of electrons.

9 Metals, Nonmetals, and Metalloids

10 NOT REACTIVE! DO NOT FORM MOLECULES OR COMPOUNDS! Noble Gases

11 What type of elements are these?

12 Metals, Nonmetals, and Metalloids Metals Metallic character refers to the properties of metals (shiny or lustrous, malleable and ductile, oxides form basic ionic solids, and tend to form cations in aqueous solution). Metallic character increases down a group. Metallic character decreases across a period. Metals give up electrons easily, forming positive ions.

13 Fr Au Al Pt React  lose electrons to nonmetals; become a positive ion (cation) Au, Pt: Are exceptions they are very unreactive! e

14 Fr Au Al Pt Melting and boiling points Increase temperature of MP and BP Increase

15 What type of elements are these?

16 React  Gain electrons from metals; become a negative ion (anion), or share with nonmetals. e-

17 Melting and boiling points Increase Temperature of MP & BP. Increase

18 What type of elements are these?

19 React  Gain or Lose electrons; become a cation or anion. Metalic and nonmetalic properties. e- +

20 chemistry.org.uk/alevel/module1/trends0.htm jectfolder/flashfiles/matters/periodicTbl2.html

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