Atomic Structure Flashcards

Terms Definitions
quantom of light
The majority of an atom is empty space.
Who discovered the electron?
J.J. Thomson
unstable isotopes prone to radioactive decay
alkali metal
an element in group 1A
What is Thomson's atomic model?
'plum pudding'
Neutron-to-proton ratio
determines the type of radioactive decay (if any) that occurs
Atoms of the same element with different mass numbers due to their different number of neutrons
the central part of the atom, containing protons and neutron
When Ernest fired the alpha particles through a thin piece of gold foil, what did he expect the particles to do?
Where is the mass of the atom?
gold-foil experiment
That atoms have a small, dense, positively-charged nucleus was discovered by _____ when he performed his ______.
nuclear fission
occurs when a very heavy nucleus splits into more stable nuclei of intermediate mass
all man-made elements
all natural elements with an atomic number greater than 83
isotopes that vary from a 1:1 ratio of neutrons to protons
What elements are radioactive?
gamma emission
type of radiation that almost always follows alpha and beta emissions
critical mass
the minimum amount of nuclide that provides the number of neutrons needed to sustain a chain reaction
mass number
the total number of protons and neutrons in the nucleusof the atom
atomic orbital
the region around an atomic nucleus where an electron is likely to be moving
What are atoms of the same element that have different masses (different amounts of neutrons)?
Rutherford's atomic model:
detected the tiny positive charge nucleus
a change in the identity of a nucleus as a result of a change in the number of its protons
alpha emission
results in the reduction of a nucleus by 2 protons and 2 neutrons
What is the electrical charge of an electron?
Negative (-)
atomic #
the number of protons in the nucleus of an element
atomic mass
the weighted average mass of the atoms in a naturally occuring sample of an element
Why could Rutherford conclude that there was a small, dense, area of positive charge?
some particles were deflected
What are the three subatomic particles?
protons, neutrons, and electrons
Nuclear chain reaction
a reaction in which the material that starts the reaction (such as a neutron) is also one of the products and can start another reaction
What particles are in the nucleus of an atom?
Protons & Neutrons.
heisenberg's uncertainty princple
it is impossible to know both the volocity and the position of a particle at the same time
What does Thomson's 'Plum Pudding' not have?
a nucleus and neutrons
What is an atom?
Smallest particle of an element that retains the chemical properties of that element
What is a Shell Energy Level?
The approximate location of electrons in the electron cloud surrounding the atomic nucleus.
What is a cathode ray?
stream of electrons produced at the negative electrode of a tube containing a gas at low pressure
What did John Dalton propose?
elements were composed of atoms and only whole-number of atoms can combine to form compounds
What is the atomic mass?
weighted average mass of the atoms in a naturally occurring sample of an element
What do the "anatomy" af an atom have?
a nucleus and electron could
What is the meaning of the Atomic Number?
Atomic Number = # of Protons.
What actually happened with the most of the alpha particles?
they went straight through the gold foil undeflected
What does John Dalton's Modern Atomic Theory state?
atoms are divisible and an element can have atoms with different masses
Do we know the exact location of electrons in the electron cloud?
No. The exact location of electrons cannot be known for certain. We can only predict the approximate & probably location of the electrons in various shell energy levels, from closest to the nucleus to further and further from the nucleus.
What would you do to calculate atomic mass?
1. Multiply the mass of each isotope by its % natural abundance (in decimal form, rounded 2 to the left)
2. Add the answers
From the Periodic Table, how do you find the # of Neutrons in an atom?
# of Neutrons = Atomic Mass - Atomic Number. or Atomic Mass - # of Protons.
positively charged subatomic partical
ground state
the lowest energy level
the family of nonmetals including fluorine and chlorine
What was Rutherford's atomic model?
"nuclear atom"
alpha particle
heavy-particle radiation that is made up of 2 protons and 2 neutrons (helium nucleus)
has a 2+ charge
danger and penetrations levels are low
Nuclear forces
The short-range forces that hold nucleons together within the nucleus of an atom
Atoms identified by the number of protons and neutrons in the nucleus
nuclear fusion
occurs when light-mass nuclei combine to form a heavier, more stable nucleus
usually occurs at extremely high temperatures
a horizontal row of the periodic table
Who was the Greek philosopher among the first to suggest the existence of atoms?
nuclear reactions
reactions that affect the nucleus of an atom
ionization energy
the energy needed to remove an electron from a gaseous atom
What are electrons?
subatomic particle that are negatively charged
The majority of the atom is what?
Empty space
Atomic number
Indicates the number of protons in an atom
What is an Ion?
An atom with an electric charge.
What is the electrical charge of a neutron?
Neutral (o)
atomic emission spectrum
lines of colored light obtained by passing the light emitted by an element through a peism
How is hyphen notation expressed?
element-# #of p+ and neutrons
What did Democritus call natures best particle of an atom?
indivisible and indestructible
Electron cloud
Most of the atomic radius is due to ___.
quantum of energy
the amount of energy required to move an electron level to the next higher one
What is a period?
each horizontal row of the periodic table
zero mass relative to p+ and n0
in electron cloud outside of nucleus
What is the charge, mass and locations of electrons in the atom?
What are the three particles in an Atom?
Protons, Neutrons & electrons.
Why could Rutherford conclude that the atom is mostly empty space?
some alpha particles went through
What does I amu equal?
1/12 the mass of a carbon-12 atom
What is the mass number?
total # of p+ and neutrons in nucleus.
E  = energy
m = mass
c = speed of light
Formula used to calculate the energy produced from mass conversions
What did Thomson detect that the electron has?
a certain amount of negative charge per unit of mass
Why can Dalton's ideas be called a theory?
He changed Democritus' ideas into a theory that could be tested.
How does an atom gain an electrical charge?
It gains or loses one or more electrons.
How did J.J. Thomson know the ray was composed of negatively charged particles?
the particles deflected by a magnetic field in the same way as a wire carrying an electrical current
What is the nucleus of an atom?
The center. The part of the atom with the most mass.
concentric rigns
electrons equal what?
Has no charge
Avogadro's number
6.022 x 10^23
Found outside the nucleus
Reasoning from generalizations to infer the outcome in particular cases.
Electrically charged atoms or groups of atoms
Line Spectrum
an electromagnetic spectrum consisting of discrete lines, usually characteristic of excited atoms or molecules
The substance that all physical properties are composed of
Isotopes of the same element have different numbers of these
electric forces
The forces between positive and negative charges.
Ernest Rutherford
Gold foil experiment. Some particles get deflected. A dense center of positive charge that contains most of the mass. Credited with discovering the NUCLEUS. Calls the positive charge protons
electric field
The field around charged particles that exerts a force on other charged particles.
Gold Foil Experiment
experiment involving shooting alpha particles at gold foil and observing them going through and bouncing off determining that the nucleus of an atom has a positive charge.
Philosopher who was the first to believe that all matter consisted of extremely small particles that could not be divided
how much, number written as a %
valence electrons
Outermost electrons of atoms; usually those involved in bonding.
move rapidly around the nucleus, have a negative charge, and a mass of 1/1836 A.M.U.
What is this also know as?
Mass Number
electron configuration
the arrangement of electrons in the orbitals of an atom
The smallest part of an element that still represents that element
idea that there are 4 elements: earth, air, fire, and water and also believed in the continuous theory of matter
noble gases
group 18 elements which are extremely unreactive
Cathode Ray
in a cathode ray tube, electrons travel as a ray from cathode(-) to the anode (+). A television is a specialized type of cathode-ray tube.
has positive charge
two(2) particles found in the nucleus
Alkali Metals
In the periodic table, what is column 1 (with the exception of Hydrogen) called?
Excited state
The state of higher energy above the ground state
belated filling
occurs when electrons are added to a sublevel beneath the principal level (Sc adds to 3d after 4s)
The simplest form of matter that has a unique set of properties; an element can not be broken down into simpler substances by chemical means
a region in an atom where there is a high probability of finding electrons
Protons and Neutrons
What has a mass of about 1 amu?
Has a mass of about 1/2000th of an amu (less than 1 amu)
Electron or Lewis dot structures
models that represent the chemically active part of an atom. It cosists of the elements symbol and dot that represent valence electrons
What are the two regions every atom consists of?
Nucleus and Electron Clous
What makes a nucleus unstable?
When the ratio of neutrons to protons is off. Radioactivity is an attempt ot correct the ratio of neutrons to protons. All elements with atomic # about 83 are radioactive.
How would you figure out the density of a proton, if you have its mass and its volume?
What assumption are you making?
Density = mass/volume
You are making the assumption that there is little empty space between atoms.
The Rutherford Atomic Model - Nuclear Atom
- In the nuclear atom, the protons and neutrons are located in the nucleus
- The elctrons are distributed around the nucleus and occupy almost all the volume of the atom
P Sublevel
Atomic Mass Unit
Protons and neutrons
the unit of frequency
a trivalent metalloid element
an element with 6 protons
splitting large nuclei in half
Change caused by radioactive decay
Electrons with greater amount of energy are found in the innermost levels of atoms. (true or false)
energy formula
[6.63 x 10^(-34)] x frequency
elements with 8 valence electrons are said to have a complete BLANK and are considered chemically stable—that is, they are less likely to react.
nuclear radiation
the penetrating rays and particle emitted by a radioactive source
what is the charge of an electron
A (-) Charged Plate
Repels the cathode ray
The closer electrons are to the nucleus, the ____ the attraction
Mass Spectrometer
Determines the relative atomic masses of atoms;
1. A sample of an element is first vaporized
2. Goes into ionization chamber and is bombarded with electrons (positive ions formed)
3. Positive ions are accelerated by an electric field
4. Deflected by a magnetic field (lighter ions are deflected more than heavy ions)
Force of attraction that depends on the mass of two objects and the distance between them; responsible for accelerating an object toward the Earth.
Magnetic quantum number
Designated as M(L), this describes what characteristic of a given electron. (values L to -L)
Lanthinide Series
Follow the element lanthanum. Are used in motion pictures apparently.
neutrons mass
neutron is greater than protons by .1%
Atoms of the same element that have different numbers of neutrons and different mass numbers
Valence Electron
the electrons that are the farthest away from the nucleus of an atom and involved in chemical reactions
Chemical Reaction
Change of one or more substances into other substances
Dalton's atomic theory
The first theory to relate chemical changes to events at the atomic level.
Energy Levels
The energy levels must be filled in order, from the inside out. (2, 8, 8.) Each energy level must be full before moving to the next.
form of saturated fatty acid room temp?
solid, example lard
Beta Decay
0/-1e or 0/-1 B
A high speed electron witha charge of -1. Medium Penetrating power and medium ionizing power. Can be blocked by a sheet of lead.
valence electrons, reactivity
BLANK BLANK are the electrons in the highest energy level. It is these electrons that determine the BLANK of an element.
some people don't forget
a mnemonic for the order of the sublevels s,p,d,f
What is 96 % human body (chemical composition)
hydrogen, carbon, nitrogen, oxygen
What is an ion?
a neutral atom that gains or looses electrons and becomes charged.
Angular momentum, l, Sublevel,s, p, d, f
The Second Quantum Number is called: BLANK BLANK; the symbol is: BLANK; which indicates the: BLANK; & its values are: 0, 1, 2, 3 (or BLANK, BLANK, BLANK, BLANK)
atomic mass unit (amu)
is equal to 1/12 of the mass of a carbon-12 atom; each individual proton and neutron has a mass of about 1 amu; each individual electron has a mass of about 1/1836 amu (very, very, very small)
What is the oxidation state of an atom?
the charge it would have if the compound were ionic
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