+

Chapter 7

The Periodic Table

Chapter 7

+

+ Organizing the Elements Prior to 1860

There were 63 known elements

No know pattern had been determined

Although new elements might be accidentally discovered from time to time, it was generally believed that all of the elements had been discovered

+ Who Invented It???Dmitri Mendeleev

(1860’s) Found a pattern. When organized by

atomic mass Properties were periodic

(repeating pattern) Elements could be

predictedHowever, a few

elements did not fit...

+ Who Invented It??? Henry Moseley (1914) If the elements are arranged

by atomic number they fit! Our periodic table is

arranged by atomic number.

+ Periodic Law As more and more

elements have been discovered each new element has supported periodic law

“Chemical and physical properties of elements are periodic functions of their atomic numbers.”

C & P properties repeat and can be predicted!

+

Groups (families) From top to bottom, or

column Elements in a family have

similar physical properties

Periods From left to right, or row Elements follow a

repeating pattern (periodicity) as you go from left to right, each element changing its reactivity and other properties based on this pattern

29

Cu

47

Ag

79

Au

Gold, silver and copper share similar properties and belong in the same group Li Be B C N O F Ne

Na Mg Al Si P S Cl Ar

HeH

++ + _ __

+

Group 1- Alkali Metals Group 2- Alkaline Earth Metals Groups3-12- Transition Metals Group 17- Halogens Group 18- Noble Gases

+ Three Classes of Elements

Metals Left side of the table Shiny, malleable, ductile, conduct heat and electricity

Nonmetals right side of the table Dull, brittle, poor conductors

Metalloids Either side of zigzag line (there are six of them) Have some of the properties of metals, but not all, properties can change under certain conditions (semi-conductors)

Metals lithium, calcium, iron,

gold, aluminium

Nonmetals carbon, oxygen,

helium, neon

Metalloids boron, silicon,

germanium, arsenic, antimony, tellurium

+

Also called…

_______________

Groups of the Periodic TableA

lkal

i Met

als

Alk

alin

e Ea

rth

Met

als

Transition Metals

Lanthanides

ActinidesH

alog

ens

Nob

le G

ases

HMetals

Metalloids

Nonmetals

Rare-Earth Metals

B

Si

Ge As

Sb Te

+ Group 1: Alkali MetalsMetalsOnly 1 electron in their outer levelVery Reactive-will easily give up

their electronSoft, silver colored, shiny, low

densityExamples: Li, Na, K, Rb, Cs, Fr

+Group 2: Alkaline Earth Metals Metals 2 electrons in outer level Very Reactive, but less reactive than

Group 1 (have 2 electrons to give up) Silver colored, more dense than Group

1 Examples: Be, Mg, Ca, Sr, Ba, Ra

+Groups 3-12: Transition Metals Metals 1 or 2 electrons in outer level

Reactive, but less reactive than Group 1 or Group 2

Shiny, good conductors of heat and electricity, more dense than Group 1 or Group 2

Examples: Ni, Cu, Pt, U

+Lanthanides and Actinides Transition Metals in Periods 6 and 7

Moved to the bottom to make room.

Lanthanides follow lanthanum (La)

Actinides follow actinium (Ac)

+Group 13: Boron Group 1 Metalloid / 4 Metals

3 electrons in outer level

Reactive

Solid at room temperature

Examples: B, Al, Ga, In, Tl

+ Group 14: Carbon Group 1 Nonmetal / 2 Metalloids / 2 Metals

4 electrons in outer level

Reactivity varies

Solid at room temperature

Examples: C, Si, Ge, Sn, Pb

+Group 15: Nitrogen Group 2 Nonmetals / 2 Metalloids / 1 Metals

5 electrons in outer level

Reactivity varies

All but Nitrogen (N) solid at room temperature

Examples: N, P, As, Sb, Bi

+Group 16: Oxygen Group 3 Nonmetas / 1 Metalloid / 1 Metal

6 electrons in outer level

Reactive (trying to get a full shell)

All but oxygen (O) are solid at room temperature

Examples: O, S, Se, Te, Po

+Group 17: Halogens All Nonmetals 7 electrons in outer level VERY Reactive Bad conductors of heat and

electricity React violently with Alkali Metals

(Group 1) to make “salts” such as NaCl

Never found alone in nature, always as a “salt”

Examples: F, Cl, Br, I, At

+Group 18: Noble GasesAll Nonmetals8 electrons in outer level (2 for

Helium)Not ReactiveColorless, odorless gasesUsed in light bulbs (Argon, Xenon,

Neon, Helium)Examples: He, Ne, Ar, Kr, Xe, Rn

+ Hydrogen: Its Own Group Part of Group 1, but unique. Nonmetal 1 electron in outer level Reactive (easily gives up

electron) Colorless, odorless gas at

room temp. Reacts explosively with

oxygen. Used in rocket fuel. Most common element in the

universe Hydrogen atoms cause acidity

+A

lkal

ine

Eart

h M

etal

s

Transition Metals H

alog

ens

Nob

le G

ases

H

Alk

ali M

etal

s

Lanthanides

Actinides

Alk

alin

e Ea

rth

Met

als

Hal

ogen

s