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MIDDLETOWN HIGH
SCHOOL SOUTH
BIOLOGY
BOOKLET 9
NAME: _________________________________
CLASS: _____________
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LEARNING OUTCOMES
1. Understand that all matter is made of elements, and that all elements
are made of atoms.
2. Describe the structure of an atom in terms of protons, neutrons and
electrons.
3. Describe the properties of protons, neutrons and electrons.
4. Name the particles that make up the nucleus of an atom.
5. Understand that the atomic number is this is the number of protons in
the nucleus of an atom.
6. Understand that all atoms of the same kind will have the same atomic
number.
7. Understand that the atomic mass is the number of protons and
neutrons present in the nucleus of an atom.
8. State that chemical bonds are where energy is stored between atoms.
9. Understand that a compound is made up of two or more different
atoms bonded together.
10. Describe the difference between ionic and covalent bonding.
11. Understand that energy is neither created nor destroyed; it is simply
converted from one type of energy into another.
12. State that an endothermic reaction is one that absorbs heat.
13. State that an exothermic reaction is one that gives out heat.
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MATTER AND ENERGY ARE RELATED

All matter is composed of elements.

Atoms are the basic building blocks of all matter and the smallest
particle of an element.

Atoms are microscopic, but groups of atoms form molecules that can
be seen.

The arrangement of atoms when they are combined, determines the
characteristics of the matter we see.
THE STRUCTURE OF AN ATOM

Atoms are the basis of chemistry. They are the basis for everything in
the Universe.

All matter is composed of very small structures called atoms.

Are there three basic parts of an atom: electrons, protons,
and neutrons.
 The electron always has a "-", or negative, charge.
 The proton always has a "+", or positive, charge.
 If the charge of an entire atom is "0", or neutral, there are equal
numbers of positive and negative pieces.

Neutral means there are equal numbers of electrons and
protons.

The third particle is the neutron. It has a neutral charge, also
known as a charge of zero.
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
All atoms have equal numbers of protons and electrons so that
they are neutral. If there are more positive protons or negative
electrons in an atom, you have a special atom called an ion.
 The protons and neutrons are
always in the center of the atom,
known as nucleus.
 The nucleus in an atom is a place
where you find protons and neutrons.
 The electrons are always found
whizzing around the center in areas
called shells or orbitals.
ELECTRONS AND ORBITALS
• Electrons are arranged in different shells around the nucleus.
• The innermost shell - or lowest energy level - is filled first. Each
succeeding shell can only hold a certain number of electrons
before it becomes full.
• The innermost shell can hold a maximum of two electrons, the
second shell a maximum of eight, and so on.
• Look at the diagram of the chlorine atom below. How many
energy levels are there? How many electrons are there in
each energy level?
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•
The atoms of elements are different from each other in specific ways:
•
Atomic number: this is the
number of protons in the nucleus of
an atom. It is used to identify
different elements
•
Atoms of the same elements have
the same number of protons in the
nucleus.
•
Different elements have different number of protons in the nucleus. For
example, Hydrogen has 1, Helium has 2, etc.
•
Atomic Mass is the number of protons and neutrons in an atom.
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Task 1: complete the following questions and check your answers with
your teacher.
1. The subatomic particles of an atom include all of the following EXCEPT
A) codons
B) protons
C) neutrons
D) electrons
2. The positively charged particles found in atoms are called
A) codons
B) protons
C) neutrons
D) electrons
3. Which of the following is a true statement about the nucleus of an atom?
A) It is negatively charged.
B) it contains electrons and protons
C) It contains protons and neutrons
D) It contains protons and electrons.
Using your period table, answer the following questions:
4. What is the atomic number of the element gold?
5. What is the atomic number of the element arsenic?
6. What is the atomic mass of francium?
7. What is the atomic mass of barium?
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CHEMICAL BONDING
•
Chemical bonds are formed when atoms are held together in
predictable ways to form molecules.
•
Energy is stored within a molecule’s bonds.
•
Atoms form bonds with other atoms because of attractions between
their electrons.
•
Compounds are substances that are formed when two or more
different atoms combine in definite proportions.
•
Compounds can be represented by using shorthand called the
chemical formula. Common examples are H2O or NaCl (table salt)
•
The physical/chemical properties of atoms change when compounds
are formed.
•
Ionic bonds are formed when electrons are transferred from one atom
to another and now the atoms are attracted to each other (opposite
charges attract)
•
Sodium and Chlorine is a good example
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•
Covalent bonds are bonds formed when atoms share electrons. The
outermost electrons are shared by both atoms at the same time.
•
A great deal of energy is needed to make or break covalent bonds.
•
Most food nutrients are made of molecules formed by covalent bonds
(carbohydrates, fats, proteins)
•
Enzymes (chemicals that speed up the rate of a chemical reaction
without being changed themselves) are needed to promote this
reaction.
SUMMARY OF COVALENT AND IONIC BONDING
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ENERGY

Energy is not lost or created; it is simple converted from one type into
another.

The different types of energy are:
1. Light energy
2. Sound energy
3. Heat (thermal) energy
4. Chemical energy
5. Nuclear energy
6. Kinetic (movement) energy
7. Electrical energy
8. Potential (stored) energy

Energy changes in the body occur by being changed. When food is
broken down by the digestive system, some energy is still stored in the
smaller molecules and some energy is lost as heat.

When energy requirements are low, organisms store potential energy
from the food they eat into large storage molecules (glycogen and fat).

When energy requirements are high, organisms convert some of the
potential energy (stored energy) into mechanical energy (kinetic).

ATP (adenosine triphosphate) is the chemical form of energy that
your cells use because it acts like an energy carrier.

Cells cannot use sugar directly, so it must be converted into ATP
first. ATP is like a battery that can be recharged by a process called
aerobic respiration.
ENDOTHERMIC AND EXOTHERMIC REACTIONS

Energy (heat) many times is absorbed or released when bonds are
broken and rearranged between atoms of molecules.

Endothermic reactions: reactions that
absorb heat energy
o breaking water to make O2 and H2

Exothermic reactions: reactions that
release heat
o Explosion, burning sugar in your
cells
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Task 2: Your teacher will assess your knowledge of the following key
terms. Make sure you understand what these words mean.
Atomic Number
Number of protons in each atom of an
element
Atomic Mass
Number of protons and neutrons in
an atom
Chemical bond
Force that holds two atoms together
Chemical formula
Group of symbols used to show the
kinds and number of atoms in a
compound
Ionic bond
Chemical bond formed when
electrons are transferred from the
outer energy level of one atom to the
outer energy level of another atom
Ion
Atom that develops an electric charge
when it loses or gains electrons to fill
its outer energy level
Covalent bond
Chemical bond formed when atoms
share electrons at the same time
Compound
Substances that are formed when two
or more different atoms combine in
definite proportions
Reaction that absorbs heat energy
Endothermic reaction
Exothermic reaction
Reaction that gives out heat energy
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