Download PowerPoint Lecture Chapter 17-20

Atoms are the building blocks
of most matter.
Solids can be described in
terms of crystal structure,
density, and elasticity.
In the liquid phase, molecules
can flow freely from position
to position by sliding over one
another. A liquid takes the
shape of its container.
Gas molecules are far apart
and can move freely between
collisions.
Unit II: Properties of Matter
(Chapters 17-20)
I. Elements (17.1)
A. atoms– the building blocks of matter
B. Element– material made up of only one kind of
atom
1. Earth formed from only
about a dozen elements
2. Many elements are
relatively rare.
3. Living things composed primarily of 5 elements
(oxygen (O), carbon (C), hydrogen (H), nitrogen
(N), and calcium (Ca)
4. lightest element is Hydrogen (H)
a. Most abundant element in the universe (90%
of all atoms in known universe)
b. Helium makes up most of the remaining 10%
(second lightest element. Relatively rare on Earth
however)
5. Heavier elements by hydrogen fusion reactions
within stars.
6. Nearly all elements on Earth are remnants of stars
that exploded before the solar system came into
being
II. Molecules (17.5)
A. molecule– when two or more atoms
combine to form larger particle.
B. Matter that is gas or liquid at room
temperature is usually made of molecules
1. Matter made of molecules may contain all the
same kind of molecule, or be a mixture of different
kinds of molecules
2. Metals and crystalline minerals made of atoms
that are not joined in molecules
III. Compounds (17.6)
A. compound– substance made of atoms of
different elements in a fixed proportion
1. chemical formula– tells proportions of
each kind of atom in compound
2. A compound may or may not be made
of molecules
Alpha Lipoic Acid
C8H14O2S2
Chemical
formula
B. Compounds have different properties from the
elements of which they are made
IV. The Atomic Nucleus (17.7)
A. nucleus– center of atom containing protons
and neutrons
1. Almost all mass of atom exists here
2. Nucleus occupies only trillionth of the
volume of an atom
B. Contains protons (+ charge) and neutrons
(neutrally charged)
1. Atoms with same number of protons
belong to same element
2. Number of neutrons may vary for given
element (called isotopes of that
element)
C. Atomic number– number of protons found in
nucleus. Used to classify atoms
V. Electrons in the Atom (17.8)
A. electrons- (-) charged particle that orbits the
nucleus of atom
1. Electron number usually equals number of
protons (say that it is electrically neutral atom)
2. electron mass 1/1800 of proton or
neutron
B. Periodic table– a chart that lists atoms by their
atomic number and their electron arrangement
V. The Phases of Matter (17.9)
A. Matter exists in 4 phases (solid, liquid, gas,
plasma)
1. plasma– predominant phase of matter
in universe
a. consists of positive
ions and free
electrons
b. exists only at very
high temperatures
B. In all phases of matter, atoms are in constant
motion
1. solids– atoms and molecules vibrate about
fixed positions.
2. liquids– increased vibration cause molecules to
“shake apart” into nonfixed positions (taking shape
of container)
3. gasses– when additional energy added to cause
molecules to break away from one another
C. All substances can be transformed from one
phase to another
Assessment Questions
1.
The number of different elements known to humankind are
a. approximately 115.
b. more than a thousand.
c. in the millions.
d. in the billions.
Assessment Questions
1.
The number of different elements known to humankind are
a. approximately 115.
b. more than a thousand.
c. in the millions.
d. in the billions.
Answer: A
Assessment Questions
2.
Compared with the wavelength of visible light, atoms are
a. about the same size.
b. smaller.
c. larger.
d. fuzzier.
Assessment Questions
2.
Compared with the wavelength of visible light, atoms are
a. about the same size.
b. smaller.
c. larger.
d. fuzzier.
Answer: B
Assessment Questions
3.
Which of these statements is correct?
a. Atoms that make up your body were formed in ancient stars.
b. Atoms that make up your body were previously a part of your
neighbors’ bodies.
c. Atoms that make up your body are in motion at all times.
d. all of these
Assessment Questions
3.
Which of these statements is correct?
a. Atoms that make up your body were formed in ancient stars.
b. Atoms that make up your body were previously a part of your
neighbors’ bodies.
c. Atoms that make up your body are in motion at all times.
d. all of these
Answer: D
Assessment Questions
4.
Brownian motion has to do with the
a. size of atoms.
b. vibrations of atoms.
c. random motions of atoms and molecules.
d. rhythmic movements of Brownians.
Assessment Questions
4.
Brownian motion has to do with the
a. size of atoms.
b. vibrations of atoms.
c. random motions of atoms and molecules.
d. rhythmic movements of Brownians.
Answer: C
Assessment Questions
5.
Molecules are composed of
a. atoms.
b. electrons and protons.
c. atomic nuclei.
d. particles larger than atoms.
Assessment Questions
5.
Molecules are composed of
a. atoms.
b. electrons and protons.
c. atomic nuclei.
d. particles larger than atoms.
Answer: A
Assessment Questions
6.
A compound is composed of different kinds of atoms
a. mixed together.
b. moving at the same speed.
c. in definite proportions.
d. in the gaseous form.
Assessment Questions
6.
A compound is composed of different kinds of atoms
a. mixed together.
b. moving at the same speed.
c. in definite proportions.
d. in the gaseous form.
Answer: C
Assessment Questions
7.
Most of the mass of an atom is in its
a. isotopes.
b. nucleus.
c. electrons.
d. electric charge.
Assessment Questions
7.
Most of the mass of an atom is in its
a. isotopes.
b. nucleus.
c. electrons.
d. electric charge.
Answer: B
Assessment Questions
8.
The shell model of the atom views electrons as occupying
a. shells.
b. three-dimensional orbitals.
c. circular or elliptical orbits.
d. standing waves.
Assessment Questions
8.
The shell model of the atom views electrons as occupying
a. shells.
b. three-dimensional orbitals.
c. circular or elliptical orbits.
d. standing waves.
Answer: A
Assessment Questions
9.
A plasma
a. is an electrically charged mixture of ions and electrons.
b. is a mixture of neutrons and protons with no charge.
c. exists at very low temperatures.
d. is another name for the solid phase of matter.
Assessment Questions
9.
A plasma
a. is an electrically charged mixture of ions and electrons.
b. is a mixture of neutrons and protons with no charge.
c. exists at very low temperatures.
d. is another name for the solid phase of matter.
Answer: A