Download Chemistry: Nuclear Theory

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Chemistry
Chemistry: Nuclear Theory
Goals: Be able to identify different Subatomic Particles and how they combine in different ways
to form different elements and their isotopes.
Definitions:
 Element: a particular kind of atom with a certain number of protons that has certain
properties
 Electron: Tiny, negatively charged particles that orbit the atom’s nucleus in uniform
patterns in clouds. Must be equal to number of protons to have no charge.
 Proton: Larger, positively charged particle in the nucleus.
 Neutron: Particle in the nucleus with no charge. Same size as Proton
 Atomic Number: represents number of protons
 Atomic Mass: the weight of the atom in AMUs (atomic mass units) which are roughly
equivalent to the weight of a proton/neutron
 Atomic Symbol: The letter that represents what element the atom belongs to.
 Isotope: Elements need only have the same number of protons. If two atoms of the
same element have a different number of neutrons, their atomic weight will be different.
 Ion: An atom that has a number of electrons not equal to its number of protons.
Tips:
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
1.001H Means Hydrogen (H), 1 proton (1), Atomic Mass 1.001 AMUs (1.001)
 You can tell the number of protons in an atom by the atomic number of its element.
Hydrogen always has 1, Oxygen always has 8, etc.
 You can estimate the number of neutrons by subtracting the atomic number from the
atomic mass, because both protons and neutrons have a mass of about 1 AMU and
electrons weigh almost nothing. Uranium (92238U) has 92 protons and weighs 238 AMUs.
We can estimate that Uranium has 146 neutrons (238-92=146)
92
 Uranium 234 is an isotope of Uranium ( 238U) that weighs 234 AMUs. It must have 92
protons to be Uranium, but it weighs about 4 AMUs less. This change in weight comes
from having 4 fewer neutrons. Uranium usually has 146 neutrons, so 92234U must have
142 neutrons.
 Ions are atoms whose number of protons (positive charge) and electrons (negative
charge) do not match. Because the number of protons cannot change, a positive ion is
one that has lost protons. A negative ion is one that has gained electrons. Ions are
written like this: Ca2+ or F-. The first one means Calcium has lost two electrons, and the
second means Fluorine has gained one. This is how ionic bonds are formed.
Example: How many protons, neutrons, and electrons does 3580Br - have?
Bromine 80 has 35 protons (top left), 45 neutrons (bottom left - top left), and 36
electrons (negative 1 means one more electron than proton)
Practice: How many protons, neutrons, and electrons do each of the following atoms have?
1. 37Li2. 1531P3+
3. 511B3-
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Chemistry
4. 53127I+
5. 1632S26. 2760Co
7. 614C
8. 46103Pd
9. 91234Pa
10. 715N3-