The document provides information about atoms and the structure of matter in three sections: 1. Atoms are the building blocks of matter and consist of protons, neutrons, and electrons. The arrangement of atoms determines the properties of different types of matter. 2. Atoms can combine to form compounds and molecules through chemical bonds. Compounds have unique properties that differ from their constituent elements. 3. Matter exists in four states - solid, liquid, gas, and plasma. The state depends on how tightly or freely the atoms and molecules are able to move. Solids have a fixed structure while gases spread freely.

2. Table of Contents
M-6
Mission 6 Notes Part I
Chapter: Matter
Section 1: Atoms
Section 2: Combinations of Atoms
Section 3: Properties of Matter

3. Atoms
1
The Building Blocks of Matter
• Matter is anything that has mass and takes up
space.
• Heat and light
are not matter,
because they
have no mass
and do not
take up space.

4. Atoms
1
Atoms
• The forms or
properties of one
type of matter
differ from those
of another type
because matter is
made up of tiny
particles called
atoms.

5. Atoms
1
Atoms
• The structures of
different types of
atoms and how
they join together
determine all the
properties of
matter that you
can observe.
• Like atoms, the same few blocks can
combine in many ways.

6. Atoms
1
The Structure of Matter
• The building blocks of matter are atoms.
• The types of atoms in matter and how they
attach to each other give matter its properties.

7. Atoms
1
Elements
• Most other objects that you see also are
made of several different types of atoms.
• Some substances are made of only one type
of atom.
• Elements are substances that are made of
only one type of atom and cannot be broken
down into simpler substances by normal
chemical or physical means.

8. Atoms
1
Elements
• Minerals usually are combinations of atoms
that occur in nature as solid crystals and are
usually found as mixtures in ores.
• Some minerals, however, are made up of only
one element.
• These minerals, which include copper and
silver, are called native elements.

9. Atoms
1
Modeling the Atom
• When something is too large or too small to
observe directly, models can be used.
• A model is a small version of a larger object.

10. Atoms
1
The History of the Atomic Model
• More than 2,300 years ago, the Greek
philosopher Democritus (di MAH kruh tuss)
proposed that matter is composed of small
particles called atoms.
• More than 2,000 years later, John Dalton
expanded on these ideas. He theorized that
all atoms of an element contain the same type
of atom.

11. Atoms
1
Protons and Neutrons
• Three basic particles
made up an atom—
protons, neutrons
(NOO trahnz), and
electrons.
• Protons are particles
that have a positive
electric charge.
• Neutrons have no electric charge.

12. Atoms
1
Protons and Neutrons
• Both particles are
located in the
nucleus—the center
of an atom.
• With no negative
charge to balance
the positive charge
of the protons, the
charge of the nucleus is positive.

13. Atoms
1
Electrons
• Particles with a negative charge are called
electrons, and they exist outside of the
nucleus.
• In 1913, Niels Bohr, a Danish scientist,
proposed that an atom’s electrons travel in
orbitlike paths around the nucleus.

14. Atoms
1
The Current Atomic Model
• Over the next several decades, research
showed that electrons can be grouped into
energy levels, each holding only a specific
number of electrons.
• Also, electrons do not
travel in orbitlike paths.
Instead, scientists use a
model that resembles a
cloud surrounding the
nucleus. Click image to view movie.

15. Atoms
1
Counting Atomic Particles
• The number of protons in an atom depends on
the element.
• All atoms of the same element have the same
number of protons.
• For example, all iron
atoms contain 26 protons,
and all atoms with 26
protons are iron atoms.

16. Atoms
1
Counting Atomic Particles
• The number of protons in an atom is equal to
the atomic number of the element.
• This number can be found above the element
symbol on the periodic table.

17. Atoms
1
How many electrons?
• In a neutral atom, the number of protons
is equal to the number of electrons.
• This makes the overall charge of the
atom zero.
• Therefore, for a neutral atom:
Atomic number = number of protons = number of electrons

18. Atoms
1
How many electrons?
• Atoms of an element can lose or gain
electrons and still be the same element.
• Atoms with fewer electrons than protons have
a positive charge, and atoms with more
electrons than protons have a negative charge.

19. Atoms
1
How many neutrons?
• Unlike protons, atoms of the same element
can have different numbers of neutrons.
• The number of neutrons in an atom isn’t
found on the periodic table. Instead, you
need to be given the atom’s mass number.

20. Atoms
1
How many neutrons?
• The mass number of
an atom is equal to
the number of protons
plus the number of
neutrons.
• The number of
neutrons is determined
by subtracting the
atomic number from the mass number.

21. Atoms
1
How many neutrons?
• For example, if the
mass number of an
atom is 14 and its
atomic number is six;
it has eight neutrons.

22. Atoms
1
How many neutrons?
• Atoms of the same element that have
different numbers of neutrons are called
isotopes.

23. Section Check
1
Question 1
__________ is anything that has mass and
takes up space.
A. calorie
B. Heat
C. Light
D. Matter

24. Section Check
1
Answer
The answer is D. Heat and light are not matter
because they have no mass and do not take up
space.

25. Section Check
1
Question 2
Particles in an atomic nucleus that have no
electric charge are __________.
A. electrons
B. neutrons
C. protons
D. quarks

26. Section Check
1
Answer
The answer is B.
Electrons have a
negative electric
charge and protons
have a positive
charge.

27. Section Check
1
Question 3
The mass number of an atom is equal to
__________.
A. the number of electrons
B. the number of electrons and protons
C. the number of protons
D. the number of protons and neutrons

28. Section Check
1
Answer
The answer is D. The number of protons and
neutrons in an atom is the mass number of the
element.

29. Section Summary
• Section 1 Summary ATOMS
• Matter is anything that has mass and takes up space
• The nucleus of an atom contains protons with a positive
charge and neutrons with no charge. Electrons, which
have a negative charge, surround the nucleus.
• Isotopes are atoms of the same element that have
different numbers of neutrons.
• Diagram of an Oxygen molecule

30. Combinations of Atoms
2
Interactions of Atoms
• There are about 90 naturally occurring
elements on Earth.
• A few elements produce many different
things because elements can combine in
countless ways.
• Each combination of atoms is unique.

31. Combinations of Atoms
2
Compounds
• When the atoms of more
than one element combine,
they form a compound.
• A compound contains
atoms of more than one
type of element that are
chemically bonded
together.
• Water is a compound in which two hydrogen
atoms are bonded to each oxygen atom.

32. Combinations of Atoms
2
Compounds
• Compounds are represented by chemical
formulas that show the ratios and types of
atoms in the compound.
• For example, the chemical formula for water
is H2O.
• The properties of compounds often are very
different from the properties of the elements
that combine to form then.

33. Combinations of Atoms
2
Chemical Properties
• A property that describes a change that
occurs when one substance reacts with
another is called a chemical property.
• The chemical properties of a substance
depend on what elements are in that
substance and how they are arranged.

34. Combinations of Atoms
2
Bonding
• The forces that hold the atoms together in
compounds are called chemical bonds.
• These bonds form when atoms share or
exchange electrons.

35. Combinations of Atoms
2
Separating Mixtures
and Compounds
• Separating the components of a mixture is a
relatively easy task compared to separating
those of a compound.
• The substances in a compound must be
separated by chemical means.
• This means that an existing compound can
be changed to one or more new substances
by chemically breaking down the original
compound.

36. Combinations of Atoms
2
Exploring Matter
• Seashells and coral reefs
contain calcium
carbonate, which has the
formula CaCO3.
• Properties of CaCO3
differ greatly from those
of its elements, calcium,
carbon, and oxygen.

37. Section Check
2
Question 1
Chemical bonds form when atoms share or
exchange __________.
A. electrons
B. neutrons
C. nuclei
D. protons

38. Section Check
2
Answer
The answer is A. Only the electrons having the
highest energy in the electron cloud can form
bonds.

39. Section Check
2
Question 2
What is the difference between a compound
and a molecule?
Answer
Compound refers to any substance in which
atoms of more than one type of element are
chemically bonded together. A molecule is the
individual unit or group of atoms connected by
covalent bonds.

40. Section Check
2
Question 3
How do compounds differ from mixtures?
Answer
In compounds, atoms of more than one type of
element are chemically bonded together.
Mixtures are composed of two or more
substances that are not chemically combined.

41. Section Summary
• Section 2 Summary Combination of Atoms
• Atoms join to form compounds and molecules. A
compound is a substance made of two or more
elements. The chemical and physical properties of a
compound differ from those of the elements of which it is
composed.
• A mixture is a substance in which the components
are not chemically combined.

42. Properties of Matter
3
States of Matter
• On Earth, matter occurs in four physical
states.
• These four
states are
solid, liquid,
gas, and
plasma.
Click image to view movie.

43. Properties of Matter
3
Solids
• The reason some
matter is solid is
that its particles
are in fixed
positions relative
to each other.
• The individual particles vibrate, but they
don’t switch positions with each other.
• Solids have a definite shape and take up
a definite volume.

44. Properties of Matter
3
Liquids
• Particles in a liquid are attracted to each
other, but are not in fixed positions as they
are in the solid.
• The particles in a liquid can change positions
to fit the shape of the container they are
held in.

45. Properties of Matter
3
Gases
• The particles that make up gases have
enough energy to overcome any attractions
between them.
• This allows then to move freely and
independently.
• Unlike liquids and solids, gases spread out
and fill the container in which they are placed.

46. Section Check
3
Question 1
___________ is a measure of the mass of an
object divided by its volume.
A. Area
B. Density
C. Force
D. Viscosity

47. Section Check
3
Answer
The answer is B. This measurement is usually
given in grams per cubic centimeter.

48. Section Check
3
Question 2
Which of the following is the most common
state of matter in the universe?
A. gas
B. liquid
C. plasma
D. solid

49. Section Check
3
Answer
The answer is C. Stars like the Sun are
composed of plasma.

50. Section Check
3
Question 3
Which state of matter spreads out and fills its
containers?
A. gas
B. liquid
C. plasma
D. solid

51. Section Check
3
Answer
The answer is A. Liquids will take the shape of
containers, but will not necessarily fill them.

52. Section Summary
• Section 3 Summary Properties of Matter
• Physical properties can be observed and measured
without causing a chemical change in a substance.
• Chemical properties can be observed only when one
substance reacts with another substance.

53. Section Summary
• Atoms in a solid are fixed in place
• Atoms in a liquid are close together but still can move
• Atoms in a gas move quickly and freely
• The only substance found in all 3 phases on Earth is
water
• Density = Mass/Volume
• If a substance is more dense than water it will FLOAT!
• If a substance is less dense than water it will SINK!