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3. Atoms are made
of a positive nucleus surrounded by negative
electrons. (AKSci -
A.1)
|
o Construct models of the atomic
structure of an element that includes accurate placement and
numbers of protons, neutrons and electrons in appropriate
energy levels, relating the terms atomic number and mass
number to the models and explaining the concepts of the
electrically neutral atom and isotopes. (for #3, #4, #5, and
#6)
|
|
4. The nucleus, a
tiny fraction of the volume of an atom, is composed of
protons and neutrons, each almost two thousand times heavier
than an electron. The number of protons in the nucleus
defines the element. In a neutral atom, the number of
electrons equals the number of protons. But an atom may
acquire a net charge by gaining or losing
electrons. (AKSci -
A.1)
|
o List the number of protons,
neutrons, and electrons in an atom of the U-238 isotope.
(for #3, #4, #5, and #6)
|
|
5. Neutrons have a
mass that is nearly identical to that of protons, but
neutrons have no electrical charge. Although neutrons have
little effect on how an atom interacts with others, they do
affect the mass and stability of the nucleus. Isotopes of
the same element have the same number of protons but differ
in the number of neutrons.
(AKSci - A.1)
|
o Use the position of calcium in
the periodic table to predict the number of valence
electrons it has and the charge on a calcium ion. (for #3,
#4, #5, and #6)
|
|
6. Scientists
continue to investigate atoms and have discovered even
smaller constituents of which neutrons and protons are
made. (AKSci -
A.1)
|
o Use the locations of potassium
and sodium on the periodic table in order to compare their
attractions for their valence electrons. (for #3, #4, #5,
and #6)
|
|
Matter may undergo
changes.
|
|
|
1. An atom's
electron configuration, particularly the outermost
electrons, determines how the atom can interact with other
atoms. Atoms form bonds to other atoms by transferring or
sharing electrons. (AKSci -
A.1, A.8a)
|
o Determine the valence electrons
in an atom using the periodic table, predict the type of
bond that an element would form with another element, test
the prediction through investigations, and explain the
chemical processes using visual representation of the ionic
or covalent bonding that results.
|
|
2. The nuclei of
some isotopes are unstable and spontaneously decay, emitting
energy. The energy from these radioactive elements has many
uses in medicine, industry, power generation, scientific
research, and warfare.
(AKSci - A.1, A.8a)
|
o Predict the particles given off
when naturally occurring U-238 decays to Th-234.
o Explain the applications of
nuclear half-lives in archeology and geology.
|
ASD Secondary
Science
If you have comments or questions concerning the Anchorage School
District Science Frameworks,
please contact
<gillam_lori@asdk12.org>
or <raymond_gail@asdk12.org>