The Periodic Table Families

Why is it important to me? Useful because it allows you to determine properties of elements by their location on the table.

Dmitri Mendeleev: Father of the Table HOW HIS WORKED… Put elements in rows by increasing atomic mass. Put elements in columns by the way they reacted. SOME PROBLEMS… Left blank spaces for undiscovered elements.

The Current Periodic Table Now the elements are put in rows by increasing ATOMIC NUMBER (number of protons)!!

Reactivity Elements are in numbered groups, or families. Most reactive groups are #1 (alkali metals) and #17 (halogens). As you move towards the middle of the table, elements become less reactive. Group #18 does not react at all (noble gases).

- Atoms, Bonding, and the Periodic Table Valence Electrons and Bonding Elements in the same family have similar properties because of their valence electrons. Number determines available electrons for bonding; max is 8. The less valence electrons an atom needs to be close to 8, the more reactive it is.

Electron Dot Diagrams Draw the symbol Determine the # of V.E. Draw that many dots around symbol

Metals 1-4 valence electrons. Gives away electrons in a reaction. Physical properties include: –Luster (shiny) –Conducts heat and electricity –High densities –High melting points –Ductile (stretched into thin wires) –Malleable (hammered into thin sheets)

Nonmetals 5-8 valence electrons. Gains electrons in reactions. Physical Properties: –No luster –Poor conductors of heat and electricity –Brittle (break easily) –Not ductile or malleable –Lower densities and melting points

Metalloids Properties of both metals and nonmetals. Along the stair step Shiny or dull. Conduct heat and electricity okay. Ductile and malleable.

Hydrogen Hydrogen is a reactive gas. In its own family because its properties are so different.

Alkali Metals 1 Valence Electron Very reactive; always combined with something else in nature (like in salt).

Alkaline Earth Metals 2 Valence Electrons Reactive; usually combined with something else.

Transition Metals 1-4 valence electrons (no pattern). Less reactive, harder metals

Boron Family 3 Valence Electrons Less reactive

Carbon Family 4 Valence Electrons Not very reactive – would rather share electrons.

Nitrogen Family 5 Valence electrons. More reactive than carbon (not much).

Oxygen Family 6 Valence electrons. Reactive; usually combined with a metal.

Halogens 7 Valence electrons Very reactive, volatile nonmetals Always combined with another element in nature.

The Noble Gases 8 Valence electrons (full). Don’t normally react with other elements.