Transcript lecture 3

Chemical reactivity
The full version will be presented Mon 31st July 2006
See you at the EXPO!
Last week our focus was;
1.
Elements and compound
2. The work and thinking of the scientists who developed
the periodic table (Hennig Brand, Johann Dobereiner,
John Newlands and Dimitri Mendeleev)
3 The physical properties of both metals and non metals
4 (Groups, periods, atomic and mass numbers)
5. The reactivity of some elements
This week please think about the following;
1. the structure of the first 20 elements
2. The special stability of the inert gases
3. Why the other elements take part in chemical reactions
4. Ionic and covalent bonding
5. Learn the symbols/charges for some
common ions.
1
Essential Info
4
7
9
11
12
14
16
19
20
23
24
27
28
31
32
35.5
40
39
40
Gp 1
Gp 2
Gp 3
Gp 4 Gp 5
Gp 6
Gp 7
Gp0
Useful links
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Who was Dmitri Mendeleev?
http://www.chemistry.co.nz/mendeleev.htm
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A Quick look at the History of the Periodic Table
http://periodictable.com/pages/AAE_History.html
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Periodic Table.com
http://periodictable.com/pages/AAE_PerTbl.html
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2 Dimensional Periodic Table
http://periodictable.com/pages/AAE_Flatprint.html
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3 Dimensional Periodic Table
http://periodictable.com/pages/1rotate.html
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The Development of the Periodic Table
http://www.chemsoc.org/viselements/pages/history_iii.html
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Web Elements
http://www.webelements.com/
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Chemical Elements.com
http://chemicalelements.com/
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Periodic Table of Elements
http://environmentalchemistry.com/yogi/periodic/
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Period Table.com for Students
http://periodictable.com/pages/AAE__studentHOME.html
The basic stucture of the atom
Essential Info
The nucleus contains
protons and neutrons
The electrons spin
around the nucleus
in orbits
NUCLEUS
Electrons in
orbits
Essential Info
The electrons are found in orbits which spin around the nucleus
Generally as the orbits get further from the nucleus their
size gets larger. They hold more electrons!
2
8
8
18
Essential Info
23
11
Na
Atomic number = number of protons and number
of electrons
Atomic Mass = number of protons and
neutrons added together
Number of neutrons = Mass number - atomic
number
Some atom structures
I discussed atomic structure at this point
Na
23
Na
11
Fluorine
Cl
F
19
9F
Potassium K
39
K
19
You should be able
to draw
diagrams for the
first twenty elements!!!!
Turn to page 497 and
find out why atoms take part
in chemical reactions
The p497 was mentioned in a Harry Potter film
It does not refer to any school text
Why do chemical reactions take place?
The inert gases are completely stable and DO NOT take part
in chemical reactions
Atoms of other elements take part in chemical
reactions so that they can become more stable. They
would all like to have the same electron arrangements
as the inert gases.
They can do this by either transferring electrons
completely
or
by sharing electrons
Why does Mg react with O?
Mg is a group 2 metal. Its
outer orbit has 2 electrons
It would like to become more like
Ne. Ne is stable and has a full outer
orbit.
O is a group 6 non metal. Its outer orbit
has 6 electrons. It would also like a full
outer orbit
By reacting together they can
achieve this!
Mg
O
;
Student guide to writing
chemical formulae
Rules leading to correct formula
2. Positive ions usually form the first
part of the name (99% cases)
3. If the formula is correct there is no
overall charge
4. If you have more than one polyatomic
ion it is placed inside brackets
Please copy into your exercise books
1. Positive ions (cations) can join to
negative ions (anions)
Essential training ions
Positive ions
+1
sodium Na+
Negative ions
-1
potassium K+
chloride Cl-
hydrogen H+
bromide Brhydroxide OHnitrate NO3hydrogencarbonate
HCO3carbonate CO3
oxide O2sulphide S2sulphate SO4
sulphite SO3
chromate CrO4
lithium Li
silver Ag+
+2
+3
fluoride F-
ammonium
NH4+
magnesium
calcium
Mg2+ Ca2+
barium Ba2+
zinc Zn2+
iron(11) Fe2+
copper Cu2+
aluminium
Al3+
chromium
Cr3+
iron(111) Fe3+
-2
-3
nitride N3phosphate PO4
IONS TABLE
http://www.eastmarinedrive.com/
Chemical Formulae 1.
IONS
sodium fluoride
CHARGES
FORMULA
NUMBERS
Chemical Formulae 2.
IONS
CHARGES
FORMULA
magnesium
fluoride
NUMBERS
Chemical Formulae 3.
IONS
CHARGES
FORMULA
silver hydroxide
NUMBERS