Studied by 2 people
How the periodic table is arranged
-there are 8 groups \n -elements who are in the same group have the same group have the same number of atomic shells horizontally \n -hydrogen is a billy no mates because it only has an atomic number of 1 and only 1 electron \n -put in order of protons \n -groups are organised in similar chemical propitiates \n -named group 0 because there are full outer shells meaning it needs no more electrons to be full \n -group 4 metals are made up of transition metals \n -4th shell
Johanne Dobereine(1817)
Came up with the 'Law of triads '
Law of Triads
put elements into groups of 3 where appearance and reactions of the elements were similar
John Newlands (1864)
Came up with the 'Law of 8'.
Law of 8
noticed that if you arranged the elements in order of their atomic mass then each element is similar to the one element places on. BUT some elements were placed in the wrong group and some were doubled-up
Dmitri Mendeleev (1869)
He grouped the 63 known elements with similar properties into columns (called groups) forming the early periodic table.
Iodine and Tellurium
Iodine and Tellurium he changed the order based on atomic weight and properties he thought reactivity was more important than mass
gaps
He left these for undiscovered elements and predicted where their places might be.
Predicted elements
These elements were later discovered and Mendeleev's predictions were found to be right and the gaps were filled
Periods
Horizontal rows on the periodic table
Elements in the same period
have the same number of electron shells
Groups
Vertical columns on the periodic table
Elements in the same groups have
the same number of electrons in their outer shell
similar chemical properties
all the elements in group 1 have
one electron on their outer shell and react in a similar way with water.
Elements in the same group also have
similar physical properties.
The word periodic in the name of the periodic table refers to
to this repeating pattern of similar properties
Group 1 elements are called
alkali metals
Group 2 elements are called
Alkaline metals
Group 7 elements are called
Halogens
there is only allowed
2 electrons in the 1st shell
you can only have
8 electrons in the other shells
In order to get a full outer shell do Group 1 elements need to
loose an electron
how the size of atoms changes as you go down a group
-the atoms get larger as you go down the group
-the outer electron gets further from the nucleus as you go down the group
How does the melting point change as you go down Group 1?
the melting point gets lower
are group 7 metals or non-metals
non metals
What is the boiling point pattern going down Group 7?
the boiling point increases
Which halogens are gases at room temperature (25 °C)?
bromine and iodine
Another name for noble gases is inert gases. What does inert mean?
non reactive
The Group 7 elements are called
halogens
Before the discovery of protons, neutrons and electrons, scientists attempted to classify the elements by arranging them in order of
there atomic weights
Elements that react to form
positive ions are metals.
Elements that do not react form
positive ions are non-metals.
proprieties of the transition elements
elements have ions with different charges, form coloured compounds and are useful as catalysts.
Note 
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