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TWEED RIVER HIGH SCHOOL
2006
PRELIMINARY CHEMISTRY
Unit 2
Metals
Part 3
As metals and other elements were discovered, scientists
recognised that patterns in their physical and chemical
properties could be used to organise the elements into a
Periodic table.

Identify and appropriate model that has been developed
to describe atomic structure.
Library Assignment: Due date –
Outline the structure of the atom by giving a brief description as to
the development of atomic structure by the following scientists:
-
Daltons Atomic Theory
-
William Crookes
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Thomson’s ‘Plum Pudding’ model.
-
Earnest Rutherford
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
Outline the history of the development of the Periodic
Table including its origins, the original data used to
construct it and the predictions used to construct it and
the predictions made after its construction.
Library Assignment: Due date Outline the development of the Periodic Table by giving a brief
description as to its development and predictions by the following
scientists:

-
John Newlands
-
Dmitri Mendeleev
-
Lothar Meyer
-
Henry Moseley
Explain the relationship between the position of elements in the
Periodic Table, and:
-
electrical conductivity
-
ionisation energy
-
atomic radius
-
melting point
-
boiling point
-
combining power (valency)
-
electronegativity
-
reactivity
Electrical Conductivity
Electrical conductivity decreases as you move from left to right
across a period. This is due to the fact that you move from metals
to semi-metals and to non-metals.
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Ionisation Energy
Ionisation energies decrease as you go down a group and increase
as you go from left to right across a period.
From classroom discussions explain why these trends occur!
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Atomic Radius
Atomic radius increases as you go down a group and decreases as
you go from left to right across a period.
From classroom discussions explain why these trends occur!
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Melting and Boiling Point
Melting and boiling points vary depending on the particular element.
They generally rise across a period until Group7 and Group 8 and
the gases.
Combining Power – Valency
For the first 20 elements, the valency of the element corresponds to
the group number.
Note: Group 8 the noble gases is also known as Group 0 as these
elements have a valency of zero.
Electronegativity
The electronegativity of an element is a measure of the ability of
the atom of that element to attract bonding electrons towards itself
when it forms compounds.
Electronegativity increases across a period and decreases down a
group.
Reactivity
The reactivity of elements generally increases down a group.
The reactivity increases across a period to Group 1V.
Assignment:

use computer-based technologies to produce a table and a
graph of changes in one physical property across a period
and down a group.
For the first twenty elements, you are to select one physical
property (eg atomic radius), find and place data on a spreadsheet
and use this to produce a computerised graph.
Both the spreadsheet and graph are to be printed out and handed
in.
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