PERIODIC TABLE OF ELEMENTS

The Elements

Naming Elements Most elements were named in latin Symbols for the elements are derived from

latin name Determined by the International Union of Pure and

Applied Chemistry (IUPAC) New elements are given a temporary 3 letter symbol

until IUPAC decides on an appropriate 2 letter symbol This committee names new elements based on

where they were discovered or to pay tribute to a notable scientist

Common Elements and Symbols

A Brief History

Johann Dobereiner (1829)

Noted a similarity among the physical and chemical properties of several groups of three elements

Middle element had mass about halfway between the atomic masses of the other two – LAW OF TRIADS

John Newlands (1864)

Arranged all known elements in order of increasing atomic mass

Law of Octaves Noticed repeating physical and

chemical properties every 8 elements

Mendeleev (1869)

Dmitri Ivanovitch Mendeleev created the first accepted version of the periodic table.

He grouped elements according to their atomic mass; elements with similar properties appeared in same column

Blank spaces were left to add elements First periodic law: elements arranged

according to increasing atomic mass show a periodic recurrence of properties at regular intervals 

Mendeleev’s Periodic Table

Modern Periodic Law

When the internal structure of atoms was discovered, Mendeleev’s periodic law was revised Elements arranged according to

increasing atomic number show a periodic recurrence of properties at regular intervals

Features of the P.T.

Groups Periods Columns of elements are

called groups or families. Elements in each family have

similar but not identical properties.

For example, lithium (Li), sodium (Na), potassium (K), and other members of group 1 are all soft, white, shiny metals.

All elements in a family have the same number of valence electrons.

Each horizontal row of elements is called a period.

The elements in a period are not alike in properties.

In fact, the properties change from metallic to non-metallic as you go across

Staircase line

Divides metals on left from non-metal on right

State of Matter Indicated by colour of the symbol

Black = solid Blue = liquid Red = gas

Families

Hydrogen

The hydrogen square sits atop Family 1, but it is not a member of that family. Hydrogen is in a class of its own.

It’s a gas at room temperature. It has one proton and one electron in

its one and only energy level. Hydrogen only needs 2 electrons to fill

up its valence shell.

Alkali Metals

Group 1 metals One valence

electron Most reactive

metals, react violently with water to make a base

soft, silver, solidsalkali metals in water

Alkaline Earth Metals Group 2 metals two valence electrons. React slowly with water Solid, react with air to form oxides React with H to form hydrides (except Be)

Transition Metals

Groups 3 - 12 Strong, hard metals High melting points good conductors of heat

and electricity. React with O to make

oxides Some react with acids Form multivalent ions

Halogens

Group 17 non-metals 7 valence electrons Extremely reactive with

hydrogen and metals Solid, liquid or gas Dull, do not conduct electricity

Noble Gases Group 18 non-metals Full valence shell gases that are extremely un-reactive

(stable) Low melting and boiling points

Lanthanides (rare earth metals)

Atomic # 57 - 70 Belong to period

(row) # 6 on the periodic table

Actinides

Atomic # 89 - 102 Belong to the 7th

period Include the

transuranic elements (elements with atomic #93 or greater – synthetic)