Difference between revisions of "Periodic Table"

Revision as of 12:41, 5 December 2018

The Periodic Table is a chart listing all the known elements arranged in order of Atomic Number and in columns of elements with similar properties.

The modern Periodic Table is based on an earlier Periodic Table made by a scientist called Mendeleev. Others had tried to arrange all the elements before, but Mendeleev was the first to arrange by both Relative Atomic Mass and chemical properties.

The modern Periodic Table is only slightly different and is arranged by Atomic Number and chemical properties.

The columns of the Periodic Table are called groups.

The rows of the Periodic Table are called Periods.

Elements have similar chemical properties when they have the same number of electrons in the Outer Shell.

The chemical properties of elements within a group are similar. However, the reactivity within a group changes as you move up or down the periods.

Group 1: The Alkali Metals all react strongly with water. The reactivity increases as you go down the group.
Group 2: The Alkali Earth Metals all react strongly with steam and acids. The reactivity increases as you go down the group.
Group 7: The Halogens all act as bleaching agents and kill bacteria. The reactivity decreases as you go down the group.
Group 0: The Noble Gases are all inert (unreactive).

The physical properties of elements within a group are similar. However, the property changes gradually as you move down the group.

The periods are arranged by the number of Electron Shells.

The chemical and physical properties of elements change as you move along a period.

Period 2 Melting Points	Period 3 Melting Points

There is a trend in the Melting Points as you move along the period.	A similar trend can be seen in the next period.

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