Download There are two types of ions

Year 9
Chemical Reactions – Acid and Alkalis - another attachment to email
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Acids and their properties
Alkalis and their properties
pH
Indicators – Red Cabbage
Word equations for reactions with acids
- Alkalis – neutralisation
- Metal
- Metal carbonates
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Acids and their formulae
Decomposition
heat
Copper carbonate
Copper oxide + carbon dioxide
Control and Coordination
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Label the eye and functions
Draw and label a neurone
Endocrine glands and the hormones they produce
Infectious diseases and the pathogens that cause them
The bodies response
Human defence mechanisms
CNS and the PNS
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Protecting the Body - Defence Barriers
The body has various defence mechanisms against pathogens.
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The first defence mechanisms / first lines of defence are those that protect the body as
possible entry points.
This protection is non-specific and aims to prevent any pathogens from entering the
body. This type of defence takes place at the body surfaces.
The body also has a second and third line of defence.
The second line of defence which comes into play when pathogens succeed in
entering the body is also non-specific. This is where cells in our immune system come
into action. E.g. phagocytes.
Non- specific means that they respond in the same way to all foreign material.
The body’s third line of defence is specific and is mediated by lymphocytes (type of
white blood cells).
The First Line of Defence – Preventing entry
A. The Skin Barrier
a. The skin forms a tough outer barrier covering over the body.
b. The outer layers of the skin contain keratin, and micro-organisms cannot
penetrate it unless it is broken.
c. The skin has its own population of harmless bacteria; their presence helps
prevent invading pathogens from multiplying.
d. Sebaceous gland in the skin secretes sebum. This sebum contains lipids that
are broken down by the skin’s harmless bacteria to produce acids that inhibit
the growth of some bacteria and fungi.
e. If the skin is broken, the blood clotting mechanism quickly forms a seal across
the wound to prevent the entry of pathogens.
f. Other glands in the skin, the sweat glands secrete salt which also helps to
inhibit bacteria.
B. Mucous membranes
 Mucous membranes line the digestive, respiratory, reproductive and urinary tracts
with a thick slimy mucous.
 This mucous membrane must be able to allow for the exchange of substances
when needed and also protect against attack.
 This protection is aided with the presence of the antibody called IgA in the
mucous.
 This reacts with potential pathogens preventing them from invading the surface.
 Fluids such as saliva, tears and nasal secretions also wash over the mucous
membranes, these fluids contain lysozyme which, breaks down cell walls of some
types of bacteria.
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C. Cilia
 Cilia are minute hairs that project from the cells lining the respiratory surfaces of
the nose and trachea and bronchial tubes.
 The cilia beat and sweep the mucus along, so that any particles breathed in and
trapped by the mucous are transported to the nose opening or to the pharynx
where they are coughed out or swallowed.
D. Chemical barriers
 Chemical barriers are provided by conditions that make the surface of the body
inhospitable for the potential pathogens.
 Example: in the alimentary canal, pathogens entering the body with food or drink
are usually destroyed by the acid environment of the stomach or the alkaline
environment in the small intestines.
 The enzyme lysozyme in tears dissolves the cell membrane of bacteria.
E. Other body secretions
Other body secretions also protect the body from invasion.
Examples:
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There are populations of harmless micro-organism in the vagina. These act on
cells shed from the walls of the vagina to create acid conditions which inhibit
growth of some bacteria and fungi.
Urine is a sterile, acid fluid. It flushes the ureters, bladder and urethra and helps
prevent the growth of micro-organisms.
Tears and saliva contain lysozymes that destroy bacteria.
Milk contains lactoperoxidase and semen contains spermine – both compounds
act against bacteria.
The Second Line of Defence – Defence Adaptations
Non- specific Responses
Assume that your first line of defence has failed. Your skin has been cut and Clostridium
tetani bacteria enter your body. Your second line of defence comes into action!
Cells in your immune system act against the foreign material.
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A. Inflammation Responses
 When the body tissue is damaged, such as by the invasion of a pathogen, the
area becomes red, hot, swollen and painful.
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The blood circulation to that part is increased and the blood vessels dilate and
become leaky. This helps to confine the pathogen while an increased number
of white blood cells help destroy it. Dead cells and toxins can be removed
quickly and repair of the tissue can begin.
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The inflammation response is mediated by chemicals such as histamine and
prostaglandins released from damaged tissues.
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The release of histamines from the damaged tissue increases the permeability
of the blood vessels, which allows the white blood cells to leave the blood
vessels and move into the damaged tissue.
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The invading pathogen are killed and engulfed by the phagocytes (type of
white blood cell).
B. Phagocytosis
 Phagocytes are one type of white blood cells which form part of our bodies
defence system. They can actively move from the blood to tissues where they are
needed to fight infection.
 Phagocytes are the white blood cells that engulf and destroy micro-organisms
and other foreign material that might enter the body. They do this in much the
same way as an Amoeba engulfs its food. This process is called phagocytosis.
 Phagocytes are produced in the bone marrow and there are two types; neurophils
and macrophages.
 Neurophils are the most common type of white blood cell and the
macrophages are the largest.
 In acute inflammation (lasting hours or days) the main phagocytes are
neurophills. In chronic inflammation (weeks or months) the main phagocytes are
macrophages.
 Macrophages are particularly active against micro-organisms that can live inside
the cells of the person they infect.
 As soon as a bacterium or other micro-organism is engulfed by a phagocyte,
enzymes and other factors are released into the vacuole containing the bacterium
and the bacterium is killed.
 A phagocyte that has already phagocytosed a bacterium can phagocytose more
bacteria far more readily than a cell that has not, in this way many more bacteria
are effectively removed and cannot cause damage to the host.
How Phagocytes Work
Question: How do phagocytes recognize and attach to a foreign body so that they can
engulf them?
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Answer:
Blood proteins assist in this task. They are called complement proteins.
Complement proteins assist in the second line of defence in a number of ways.
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Some complement proteins stick to invading micro-organisms that become more
readily identifiable by phagocytes as being foreign.
Others stimulate the phagocytes to become more active.
Some attract phagocytes to the site of the infection.
Others destroy the membrane of the invading micro-organism.
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C. The lymph System
The lymphatic system comprises a system of vessels to return lymph to the blood
circulatory system.
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Numerous thickened areas, called lymph nodes are spread along the system.
These nodes contain large numbers of white blood cells that play a central role in
the body’s second and third line of defence.
At these lymph nodes or lymph glands white blood cells called lymphocytes are
made and added to the lymph as it flows through.
Lymph nodes also engulf and destroy bacteria and filter other foreign
materials and cell debris circulating through them.
Lymph nodes may become rather tender when there is an infection nearby. They
are inflamed and enlarged by the bacteria and toxins they accumulate as they fight
the invaders.
D. Sealing off the pathogen
 When the body is unable to neutralize an antigen (foreign body), a particular type
of chronic inflammation occurs involving both lymphocytes and macophages.
 The macrophages and lymphocytes completely surround a pathogen so that it is
enclosed in a cyst. This cluster of cells is called a granuloma. The white cells
involved die, so that the pathogen is isolated from its food supply and also dies.
 The granuloma consists of a central core of dead tissue which is surrounded first
by macrophages, then lymphocytes and then fibroblasts which produce a tough
outer wall.
 Granulomas are produced in tuberculosis and leprosy.
The body’s immune response is its reaction to the invasion by foreign materials.
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These foreign materials may be viruses, bacteria, toxins or other foreign proteins.
Substances are identified as foreign by the body which then responds by trying to destroy
them.
Antigens are substances or molecules that trigger this immune response.
If the previous two systems fail to destroy the pathogen then the body’s immune system
comes into play. It depends on distinguishing between parts of the body and particles from
the outside. It is important that phagocytes are able to make this distinction otherwise they
would destroy body cells.
Waves - another attachment to email
Properties of waves
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- Wave diagram
- V=fλ
- Pitch
- frequency
Lenses
Mirrors
Electromagnetic spectrum
Shocking Stuff – Electricity
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Series and Parallel circuits
Resistance and Ohm’s Law (V = IxR)
Circuit diagrams – symbols and fuses
Electricity production and fossil fuels
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Our Place in Space
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Big Bang theory
Heliocentric and Geocentric models of the universe
- Galileo
- Newton
Telescopes – including Hubble
Life cycle of a star
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Hertzsprung-Russell diagrams
Plate Tectonics
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Plates and plate boundaries
Subduction zones
Divergent zones – sea floor spreading
Gwandaland
Evidence for continental drift
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Year 10
Atomic Theory
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Atomic structure
Atomic number; mass number; electron configuration
Periodic Table
Reaction of metals and acids – activity series
Ions – cations and anions
Nuclear technology
THE ATOM
Atoms and Molecules
An atom is the smallest part of an element which can take part in a chemical reaction.
A molecule is the smallest particle of a substance capable of separate existence. Molecules
are the basic units of compounds.
Atoms
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An atom is made up of electrons, protons and neutrons.
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Protons and neutrons are in the nucleus of an atom.
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Protons are positively charged while neutrons have no charge.
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Electrons have a negative charge.
The Periodic Table:
The Periodic Table is divided into:
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Periods (rows) and Columns.
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Groups (1 to 0 (or 8)
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Metals and Non-metals
The Groups
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Each Group number represents the number of electrons in the outer shell, (excluding
the transition metals).
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The number of electrons in the outer shell determines the reactivity of the element.
Atomic Number
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The atomic number, Z, of an element is the number of protons in the nucleus of an atom
of that element.
Mass Number
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The mass number, A, is the number of protons plus neutrons in the nucleus of an atom of
the element.
The mass number – atomic number = the number of neutrons in the nucleus.
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In a neutral atom, the number of electrons equals the number of protons.
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The electron shells represent energy levels. The way the electrons fill theses shells is
called the atoms ELECTRON CONFIGURATION.
Electron Configuration.
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There are only ever TWO electrons in the first shell.
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Up to the first twenty elements each shell has a maximum of EIGHT electrons.
The electron configuration for Hydrogen is 1
p
The electron configuration for Helium is: 2
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The electron configuration for Sodium is: 2,8,1
The Formation of Ions
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Atoms prefer to exist with full outer shells. To do this, atoms will either lose or gain
electrons.
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An ION is an atom that has either lost or gained electrons.
There are two types of ions:
1. Cation
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A cation is an atom that has LOST an electron(s).
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Cations have a POSITIVE charge.
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This positive charge comes from there being more protons (+ve) than there are
electrons (-ve).
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For example:
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The sodium ion.
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The sodium atom has one electron in its’ outer shell.
1. Anions
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An anion is an element that has GAINED an electron(s).
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Electrons have a NEGATIVE charge.
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This negative charge comes from there being more electrons (-ve) than there are protons
(+ve).
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In terms of electrostatics, opposites attract. Therefore, positive ions (cations) will attract
negative ions (anions).
When this attraction occurs, ionic compounds form.
Cars and Physics
Newton's Three Laws
of Motion
Let us begin our explanation of how Newton changed our understanding of the Universe
by enumerating his Three Laws of Motion.
Newton's First Law of Motion:
I. Every object in a state of uniform motion tends to remain
in that state of motion unless an external force is applied to
it.
This we recognize as essentially Galileo's concept of inertia, and this is often termed
simply the "Law of Inertia".
Newton's Second Law of Motion:
II. The relationship between an object's mass m, its
acceleration a, and the applied force F is F = ma.
Acceleration and force are vectors (as indicated by their
symbols being displayed in slant bold font); in this law the
direction of the force vector is the same as the direction of
the acceleration vector.
Newton's Third Law of Motion:
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III. For every action there is an equal and opposite reaction.
This law is exemplified by what happens if we step off a boat onto the bank of a lake: as
we move in the direction of the shore, the boat tends to move in the opposite direction
(leaving us facedown in the water, if we aren't careful!).
Force is measured with a spring balance in Newtons
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