Ch. 2 Outline and Worksheet Name: Per: row: 2.1 Chemical

Ch. 2 Outline and Worksheet
Name:
Per: row:
2.1 Chemical Elements
A. Matter: Matter takes up space and has mass.
1. Made up of elements: substance that cannot be broken down into other substances by a chem rxn 2. Compound: consist of 2 or more elements in a fixed ratio
3. Six elements (C, H, N, O, P, S) make up 98% of living things. B. Atomic Structure
1. Chemical and physical properties of atoms depend on specific
numbers of protons, neutrons, and electrons.
a. Protons are positively charged particles; neutrons have no
charge; both have about 1 atomic mass unit of weight. Both
are found in the nucleus
b. Electrons are negatively charged particles that orbit the
nucleus
2. The atomic mass of an atom is about equal to the sum of its
protons and neutrons.
3. All atoms of an element have the same number of protons,
which is the atom’s atomic number.
C. Isotopes
1. Isotopes are atoms with the same number of protons but
differ in number of neutrons; e.g., a carbon atom has six protons
but may have more or less than usual six neutrons.
2. A carbon with eight rather than six neutrons is unstable; it
releases rays and subatomic particles and is a radioactive
isotope.
3. Low levels of radiation such as radioactive iodine or glucose
allow researchers to trace the location and activity of the atom
in living tissues; therefore these isotopes are called tracers (used
in CAT scans)
4. High levels of radiation can cause cancerous tissues and
destroy cells; careful use of radiation in turn can sterilize
products and kill cancer cells.
E. Electrons and Energy
1. An orbital is a volume off space where an electron is most
likely to be found; an orbital contains no more than two
electrons.
2. The more distant the orbital, the more energy it takes to stay
in the orbital.
3. When atoms absorb energy during photosynthesis, electrons
are boosted to higher energy levels.
4. The innermost shell of an atom is complete with two electrons
(s orbital); all other shells are complete with eight electrons.
5. The outermost shell is the valance shell, and the number of
valance e- in the outermost shell determine many of the atoms
properties
Bonding: (2.2)
What are compounds:
TYPES:
Name: Per: row: Ch 2 Review of Chemical Bonds
Label each picture with its bond type and the names of the elements in the compound:
QUESTIONS:
1. Define the following terms:
Valence Electron
Valence Shell
2. How is the chemical behavior of an atom determined by its electron configuration
3. Why do atoms form chemical bonds?
4. Identify the type of bond described in each of the following. Use the key to indicate your answers.
A. Covalent, polar B. Covalent, nonpolar
C. Hydrogen
D. Ionic
______ Strongest bonds
of electrons between two atoms
______ Weakest type of bond
______ Attraction between oppositely charged
______ Bonds formed by the complete
portions of two different polar molecules
transfer of electrons from atom to another
______ C —C
______ Bonds formed by the equal sharing of
______ H—O—H
electrons between two atoms
______ C —O
______ Bonds formed by the unequal sharing
______ Na—Cl
5.How can you determine if the bond between two atoms is polar covalent, nonpolar covalent, or ionic
5.
Howis
can
if the
bond between
two
atoms
6. How
the you
shapedetermine
of a molecule
important
in biological
systems?
nonpolar covalent, or ionic?
is polar covalent,
_____________________________________________________________
_____________________________________________________________
_____________________________________________________________
6.
How is the shape of a molecule important in biological systems?
7. Match
the description with the correct term.
A. Anion
B. Cation
C. Ion
_____________________________________________________________
_____________________________________________________________
______Charged
atom or molecule
7.
Match the descriptio n with the correct term.
______
Negatively
charged
______
Charged
atomion
or molecule
A.
Anion
______ Negatively charged ion
B.
Cation
______ Positively charged ion
C.
Ion
______ Positively charged ion
8.
Howmany
many
electrons
are shared
between
the
of the following:
8. How
electrons
are shared
between
the atoms
inatoms
each of in
theeach
following:
Chemical Bond
9.
# of e- shared
Chemical Bond
# of e- shared
9.
is the
biological
ofweak
weak
bonds?
10.What
What
is the
biologicalimportance
importance of
bonds?
_____________________________________________________________
_____________________________________________________________
10.
What is the meaning of the following statement: “Nonpolar covalent bonds
and ionic bonds are two extremes of a continuum.”
_____________________________________________________________
11._____________________________________________________________
What is the meaning of the following statement: “Nonpolar covalent bonds and ionic bonds are
two extremes of a continuum.”
_____________________________________________________________
Biochemistry Activity #1 page 4
Other Terms to Know:
Element
Atomic number
Compound
Atomics Mass
Protons
Isotope
Neutrons
Radioactive dating
Electrons
Orbital