45 `` An event that is periodic happens once and then again at specific time
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intervals. Periodic can also be used to describe a repeating pattern.
`` Run you finger over a piano keyboard and hit all the keys and you will of course hear a repeating pattern of octaves. Every key plays a note one octave higher or lower than the key eight keys before or after. The set of seven keys A-G plays the set of notes within one octave.
`` During the development of the periodic table, chemists noticed this “law
of octaves�. Every eighth element seemed to have similar properties. However this pattern broke down as more elements were discovered and added to the table. The table itself is called periodic because it displays repeating patterns.
`` However there is more than one type of periodic table. The one printed in this book is the standard Mendeleev periodic table seen in many texts.
Getting to know the periodic table
`` The periodic table as we use it today in chemistry was first formulated by the
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Russian chemist Dmitri Mendeleev (right) in 1869. Not only did he organize the then known elements into the table, but he predicted the properties of eight unknown elements and left spaces in the table for when they were discovered.
`` It was not until 1913 that it was proved that the order Mendeleev placed the
elements was in fact the same as ordering the elements by their atomic number.
`` Before you start looking at the finer details of the periodic table it is worth getting to know the large scale structure of the table.
`` The periodic table is organized into columns called groups and rows called periods. The periodic table below shows the different groups of elements. Different groups of elements are given different names for easier reference:
Metals
Non metals
Main block elements
Alkaline Transition Earth metals metals
Metalloids
Basic metals
Non metals
Halogens
Lanthanoids Actinoids
Noble gases
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Alkali metals
Atomic number
Š2020 BIOZONE International ISBN: 978-1-927309-79-7 Photocopying Prohibited
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Alkali metals are kept in The transition metals are the most familiar metals. Iron Halogens and noble gases are often used in oil to stop them reacting. and copper are particularly important to industry. lighting to produce bright or colored lights.