Historical Development of the Periodic Table

Greek Thinkers

Proposed air, water, fire as elements and said the atom was the smallest particle

Lavoisier

Father of modern chemistry; classified metals from nonmetals and divided elements into 4 classes

John Dalton

determined the difference between compounds and elements. developing an improved method of determining their weights created the first chart by weight

Dobereiner

found that some sets of three elements could be grouped - later called ’Triads’

Dechancourtois

Created a periodic system on a cylinder.

Cannizaro

Produced accurate atomic weights for elements.

Newlands

arranged the known elements in order of increasing atomic weight, and found that elements with similar properties occurred at regular intervals

Meyer

compiled a Periodic Table of elements based on the periodicity of the properties

Mendeleev

organized the first periodic table with increasing atomic mass

Moseley

Arranged elements by increasing atomic number.

Seaborg

Separated lanthanide series from actinide series.

Atomic Radii

Half distance between identical atom nuclei.
Increases as you move down a group Increases from left to right

Ionic Size

Cations decrease; anions decrease across a period.
Increases as you move down a group

Ionization Energy

Energy needed to remove loosely held electron
from outer energy level
increases as you move up a group
Increases left to right

Electronegativity

The ability of an atom to attract e-s to itself when it is
chemically combined with another element.
Increases as you move up a group
Increases as you move across a period

most active metals

Alkali metals

most active nonmetals

groups 13-17

Crust most abundant gas

Oxygen

Ocean most abundant gas

Chlorine

Atmosphere most abundant gas

Nitrogen

Sun most abundant gas

Hydrogen

Periodic law

When elements are arranged in order of increasing atomic number, there is a periodic repetition of their chemical and physical properties.

Alkali metals

Most reactive of all metals and therefore not found in free form in nature

Very soft, can be malleable, ductile, luster, and good conductivity of heat and electricity (solid)

low density, low melting point

Alkali Metals give violent reactions when they react with

water

Alkaline Earth Metals

Reactive but not as violent as alkali metals

Low melting point Low density

Transition Metals

They come from mineral deposits in the earth’s ores and they are used for the commercial production of metals known as alloys

Variation of reactivity

Most are ductile, malleable, have color, and are good conductors of heat and electricity

Boron family

Boron is a metalloid but the rest are metals

Carbon Family

They are all solids at room temperature

Allotropes of carbon: graphite, diamond, bucky ball

Nitrogen Family

All are solid at room temperature expect for nitrogen which is a gas

Oxygen family/Calcogens

All expect oxygen are solids are room temperature

polonium is a radioactive metal

Halogens

Most reactive nonmetals and do not occur free in nature

Diatomic Molecule

2 of the same atoms bonded together

Noble gases

Colorless, odorless, tasteless

They have a filled (stable) outermost energy level

Inner transition elements (lanthanides 1st row)

Abundant, high melting points, manufacturing

Inner transition elements (Actinides 2nd row)

Small amounts, radioactive

All are synthetic or man-made