Unit 3 Atomic Structure/Nuclear Chemistry

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atom
basic unit of matter
atom
smallest particle of an element that still has the properties of that element
What are the three parts of an atom?
proton, neutron and electron
atomic number
the number of protons in an atom
What is the symbol for the atomic number?
Z
Where is the atomic number shown on the periodic table?
bottom left corner
electron
negatively charged particle of an atom; moves around the nucleus
electron dot diagram
diagram that shows the element symbol surrounded by dots representing valence electrons
element
pure substance that cannot be broken down into simpler substances by ordinary chemical means; same number of protons
energy level
a particular region where electrons can orbit a nucleus
ion
an atom or molecule that has an electrical charge because it has gained or lost electrons
cation
an atom that is positively charged; more protons than electrons
anion
an atom that is negatively charged; more electrons than protons
isotopes
atoms with the same number of protons but different number of neutrons; most isotopes are radioactive
mass number
the number of protons plus neutrons of an atom
Where is the mass number shown on the periodic table?
upper left corner of the element
neutron
particle in the nucleus of an atom with no charge
nucleus of an atom
center of an atom that contains protons and neutrons
periodic table
a chart that organizes the chemical elements and their properties
proton
a positively charged particle of an atom found in the nucleus
radioactive
able to release radiation; the nucleus decays to release particles and/or light; these emissions are called radiation
What can radiation used for?
to produce electricity in a nuclear power plant; it can also be used for atomic bombs
valence electrons
electrons found in the outermost energy level of an atom
Democritus
came up with the idea for an atom
Thomson
discovered the electron
Bohr
discovered that electrons are in orbit and each orbit can hold a specific number of electrons
Rutherford
performed the gold foil experiment; it verified that Thomson’s experiment was accurate; proved that atoms are mostly made up of space
Dalton
1. elements consist of atoms.
2. elements are pure because atoms are identical and have the same mass
3. different elements are made of different atoms and have different mass
4. atoms combine to form compounds
matter
anything that takes up space and has mass
Where is most of the mass of an atom found?
in the nucleus
radioactivity
spontaneous breaking apart of unstable nuclei
Becqueral
discovered radioactivity through x rays with uranium
Why is radiation harmful to living and nonliving things?
causes changes in structures and can cause mutations and/or cancer
What are three uses for radiation?
xrays, bombs, nuclear energy
half life
the amount of time it takes for half of the radioactive substance to decay
alpha decay
Alpha Decay is when an unstable nucleus emits an alpha particle which consists of two protons and two neutrons bound together
beta decay
An electron (or positron) emitted during the radioactive decay process. This results after a neutron becomes a proton and an electron.
gamma decay
decay characterized by emission of a high-energy proton. neutral
fission
nuclear reaction resulting from the splitting of atoms to release energy
fusion
nuclear reaction resulting from atoms forced together to release energy
What is an advantage of fusion over fission?
fusion does not release radioactive waste
Categories: Atomic Physics