Part Charge Location

Proton Positive (+) In the nucleus

Neutron Neutral ( ) In the nucleus

Electrons Negative (-) Orbiting around the nucleus

He created the periodic table of elements in 1869. At this time there were 63 elements.

He noticed that a pattern of properties appeared when he arranged the elements in order of increasing atomic mass.

The word periodic means “in a regular, repeated pattern.”

The table we read today is arranged according to increasing atomic number.

The properties of an element can be predicted from its location in the periodic table.

Each square on the periodic table includes:Each square on the periodic table includes:

Atomic numberAtomic number Chemical SymbolChemical Symbol Chemical NameChemical Name Atomic massAtomic mass

Mass number - sum of the protons and neutrons in the nucleus.

Atomic mass - the average mass of all isotopes of an element.

Atomic number - the number of protons in the nucleus.

Isotopes - atoms with the same number of protons and a different number of neutrons. Example Carbon 12, 13, and 14.

PERIODS

Horizontal Numbered 1-7 Relate to weeks

on a calendar

GROUPS (families)

Vertical Numbered 1-18 Relate to same days

on a calendar Similar

characteristics

Luster - shininess Malleable-hammered or pressed into flat sheets Ductile-pulled out or drawn into a long wire Conductive-ability to transfer heat or electricity Color-produced when heated Magnetic-attracted to a magnet or become magnetic

Chemical Properties of Metals*Reactivity-ease and speed with which an element combines, or reacts with other elements and compounds

*Corrosion-the destruction of a metal as it is exposed to other elements (rust)

Group 1 (Alkali Metals) – most reactive group of metals, shiny and soft

Group 2 (Alkaline Earth Metals) – reactive, fairly hard and good conductors of electricity

Groups 3 – 12 (Transition Metals) – hard, shiny, good conductors of electricity

Group 17 – (Halogens) – highly reactive nonmetals, salt-forming

Group 18 – (Noble Gases) – unreactive, very stable

Brittle - breaks apart easilyDullPoor ConductorsMost are gasesReactive with other elements (Group 17)

These are elements that have some characteristics of the metals and the nonmetals.

The most useful property of the metalloids is their varying ability to conduct electricity.

Semiconductors - substances that can conduct electricity under some conditions but not under other conditions

Ex. B, Si, Ge, As