Atomic theory 2 Flashcards

Terms Definitions
discovered the nucleus
Ernest Rutherford
number of neutrons vary
Ionic Bonds
gain or lose electrons
How many neutrons does carbon-14 contain?
number of electrons vary, electrons change charge of the ion
Discovered alpha, beta, and gamma particles
Ernest Rutherford
discovered that most mass and charge of atom was concentrated a small volume, shot alpha particles at gold foil, found deflection (thought it was solid ball), planetary model of atom (central nucleus with positive charge and most of mass surrounded by a ring of very small, negatively charged electrons)
JJ Thomson(1856-1940)
Created the raison pudding model. Could be broken down into negative and positive charges.
the number of protons in the nucleus
atomic number
Said that electrons have some properties of waves
Louis De Broglie
solid center of the atom that contains most of the mass of the atom
atom is the smallest unit, cannot get any smaller, everything is either atom or void
Ernest Rutherford
Showed that protons are in the nucleus, alpha particles have a negative charge
J.J. Thomson
Suggested that an atom is a positively charged sphere with electrons embedded in it.
One of the first people to state that matter is made up of atoms was?
Erwin Schrodinger
His work led to the electron cloud model
John Dalton
claimed that all elements are made of atoms
Did a gold foil experiment to make his model of the atom
Ernest Rutherford
Electons in a lower energy state will most likely be found where around the nucleus?
Near the nucleus, lower energy level
No charge
Discovered electrons
negatively charged particle
Cathode Ray Experiment.
positively charged particle
represents an element
Who discovered the neutron?
P orbital
Boe tie shaped
Law of Definite Proportions
responsible for many discoveries
accidently discovered radioactivity while investigating fluorescent minerals
-Greek Philosopher
-proposed that matter was a combination of 4 basic "elements"
-beginning of chemistry in the western hemisphere
ability to do work.
Modern day atomic model
subatomic particle with no charge
what particle did Thomson discover
objects with like electric charges
William Crookes
The Cathode Ray Tube
perfect absorber of incident radiation. produces a spectral density curve
mass spectrometer work indicates different masses for some atoms of the same element- the nucleus contains neutral particles called neutrons
help create concept of protons, isotopes and neutrons
energy levels with orbiting electrons
Niels Bohr
Proposed the planetary model.
J.J. Thompson
> electron:
negatively charged
much smaller and lighter than atoms
uniformly present in many different kinds of substances
Plum Pudding Model
First to coin the term atom
nuclear fusion
the combining of atomic nuclei
Who conducted the cathode-ray tube experiment?
Electrons bounce around in their energy levels /shells
Realized that chemical reactions often produced gases that could not be easily measured. This realization led him to develop the Law of Conservation of Matter.
number of neutrons
atomic mass- atomic number
solid to gas- rapidly heating water
made measurements of chemical change in a sealed container
1. Induced radioactivity produced by bombardment of element with a particles
2. Behave like a natural radionuclides
a. disintegrate in a definite series
b. have specific half-life
Whose atomic theory remained the accepted truth for 2000 years
True or false: Dalton's Atomic Theory had the idea that all matter is made up of small particles called atoms
nuclear reactions
reactions involving the particles in the nucleus of an atom
JJ Thompson
atoms are positive spheres with negative charges embedded in them, and electrons were scattered in a positively charged sphere.
the smallest particle an element can be divided and still remain the same substance
Bohr's Conclusion
Bohr discovered that electrons don't stay in rings, but many different shapes.
Covalent Bonding
Atoms overlap slightly, and one unpaired electron from each atom will pair together
developed the law of conservation of matter and discovered oxygen and found that air is a mixture of substances
what are protons and neutrons made of?
stationary state
corresponds to an electron that remains in a particular energy level, neither absorbing or emitting radiation
study of synthesis and analysis of matter
atoms of an element that are chemically alike but different in mass
shot alpha particles at droplets of oil and sometimes hit the oil and caused it to lose an electron, making it positive, and therefore it will move toward negative charge he has set up
He rejected the idea of the atom.
atoms form compounds that have the same amount of each element
in the nucleus
Where can a neutron be located?
oxygen family
group 16, 3 nonmetals (oxygen, sulfur, selenium) gain/share 2 electrons, diatomic molecule that you breathe, can be triatomic (0 sub 3=ozone), highly reactive, can combine with almost any other element (sulfur is used for rubber/sulfuric acid)
made law of combining volumes as well as avagadros law
optical grating
also known as a diffraction grating; used to separate light into its component colors
Atomic mass
the weighted average of all an element's isotopes.
electromagnetic spectrum
its the spectrum or series that constains all the different forms of electromagnetic radiation that exists. its arraged in order of increasing wavelength λ.
Structure of the Atom
Protons are positively charged particles found in the nucleus; All atoms of the same element have the same number of protons; One proton weighs 1 atomic mass unit (amu or u); Neutrons are particles found in the nucleus, but have no charge; One neutron also weighs 1 amu
Orbital - A region in space where electrons might be
smoke detector
blew smoke into an ionization chamber and watched the changes in ionization
Bohr Theory
electrons travel in the atom in circular orbits with quantized energy- energy is restricted to only certain discrete quantities
there is a maximum number of electrons allowed in each orbit
electrons jump to a higher level when a photon is absorbed. a photon is emitted when the electron drops to a lower level
Who was the first person to postulate the idea that all matter is made up of tiny pieces of identical matter?
A measurement of the number of waves that pass a particular point per second.
in the electron cloud
Where can an electron be located?
pure substance
a sample of matter, either a single element or a single compound, that has definite chemical and physical properties
atomic number of sulfer is 16 how many electrons are in sulfer 35
Alpha particles
travel a short distance; made of 2 Helium protons and 2 Helium neutrons
Electron Dot model
shows valence electron structure in an atom
The number of protons and neutrons for a specific isotope of an atom
Mass Number
Joseph Proust
Came up with the law of definite proportions which concluded through experimentation, that elements that compose compounds were always in a certain proportion by mass
alkaline-earth metals
are not as reactive as alkali metals because it is more difficult for atoms to give away two electrons then to give away only one when joining with other atoms.
electons are found in an electron cloud, not path
schrodinger and heisenberg
Dynamic molecular equilibrium
Atoms and molecules are in constant motion at non- Absolute zero
There are no changes in observable properties because of this movement
three products of radioactive decay
alpha particles, beta particles and gamma rays
If you cant look at it then you have to describe it as both possibilities Wave equation Sub levels of where electrons are Electron cloud model
atomic number
number of protons in an atom (which is the same as the number of electrons)
Law of conservation of matter
Matter cannot be created or destroyed.
What is quantum?
It is a finite quantity of energy that can be gained or lost by an atom. It is also known as packets of energy.
Diatomic Molecule
A pair of atoms that are joined by two covalent bonds
How many unpaired valence electrons does phosphorus, P, have?
Phosphorus has three unpaired valence electrons. Phosphorus's electron configuration is 1s² 2s² 2p⁶ 3s² 3p³. Of the three valence electrons, one goes into each of the three p orbitals, so that all three orbitals have one electron, This means all three are unpaired.
Chocolate chip cookie model
Most of the atom is positively charged with electrons scattered around the outer part of the atom
If you are hurt, what should you do?
tell the teacher at once
The electrons move away from the nucleus and speed up.
What did Bohr says happens when electrons GAIN energy?
The atom has a positively charged nucleus
What was the second major finding of the Gold foil experiment?
All matter is made up of atoms, atoms are indivisible and invisible, all atoms of one element are exactly alike but different from other elements, his concept is called the solid sphere model
What are the main points of Dalton's atomic theory?
negatively charged particle
pos charged ions
posotively charged particles
G.J. Stoney
named the election
Who said,"Atoms are uncuttable."
Democritus 440BC
Atoms are "Uncuttable"
Greek word for atom
chemists classify elements as this
number of energy levels possible
Angular Momentum Quantum #
sub-levels possible
chemical change
chemical reaction-proccess that involves one or more substances changing into new substances
-Radioactivity is the spontaneous disintegration of atomic nuclei as a result of nuclear instability
-discovered by Henri Becqueral Pierre, and Marie Curie.
Theory of matter
created by dalton
Energy levels w/ orbiting electrons
who discovered the solar system model?
density/centrifuge is pun at high speed, solid is forced to bottom
discovers that atoms contain positive charges
Discovery of Ions
Michael Faraday discovered electrically charged ions.
Svante Arrhenius explained that conductivity results from the dissociation of compounds into ions: cations and anions
Ions are formed by losing or gaining electrons.
The new substances formed from a chemical reaction
ionizing radiation
radiation energetic enough to ionize matter with which it collides.
Who said,"There is a small, dense, positivatly charged nucleus."?
Law of Definite Proportions- a given compound always contains the same proportion of elements by weight (mass)
First Scientist for a nuclear chain reaction, lead person in developing the atomic bomb
how many outer electrons do metals usually have?
what are alpha particles?
2 protons, 2 neutrons
The alkaline earth metals constitute which group on the periodic table?
Group 2A
Plato and someone else
Democritus's time
Their theory remained accepted for 2000 years
Thought everything was made up of 4 elements; Fire, Water, Earth, Air
tells how many molecules of that element
aristole/ plato
whose atomic theory remained the accepted truth for 2000 years
Aristotle / Plato
Whose Atomic Theory remained the accepted truth for 2000 years?
Neils Bohr
electrons occupy energy levels in the atom
Amadeo Avogadro
equal volumes of gases, under same conditions, have the same number of molecules
Avogadro's Hypothesis
at the same temperature and pressure, equal volume of gases contain the same number of particles. The volume of a gas is determined by the number of particles not the size of each individual particle.
Dalton's theory
All matter made up of atoms
atoms can't be created or destroyed
same atom equals same element
optical microscope
a microscope that uses lenses and bending of light to produce enlarged images of small objects
Quantum Mechanics
1920's; presented a radical picture of the atom; atoms cannot be pinpointed but they exist as a cloud outside the nucleus
A scientist who measured the charge of an electron
G.N. Lewis
-developed the electron dot model of the atom to show valence electron structure
Nuclear Fission
-discovered by lise meitner and otto han
-the nucleus of an atom splits into smaller parts releasing free protons and neutrons
elements in the same group often have similar chemical and physical properties.
Valence Electron
The electrons in the outermost energy level
periodic table
a chart of the elements showing the repeating pattern of their properties
the process of determining the age of an object by measuring the amount of a certain radioisotope remaining in that object
radiochemical dating
Empty space
What is most of the electron cloud composed of?
a shell, or level of orbit, around the nucleus of an atom
electron cloud
area outside of the nucleus where the electrons are found
physical property
property that can be seen and measured without changing composition-density,melting point
principal quantum #s (n)
(principal energy levels (n). main levels in an atom. there are 7 possible principal energy levels (n1-7) the energy of an e- increases as n increases
average atomic mass
weighted average of the atomic masses for the isotopes of an element
law of multiple proportions
States that when two elements combine to form two or more compounds, the mass of one element that combines with a given mass of the other is in the ratio of small whole numbers
Gay-Lussacs Law of Combining Volumes
At constant temperature and pressure, the volumes of reacting gases can be expressed as a ratio of simple whole numbers. 2 volumes of H reacts with 1 volume of oxygen-> 2 volumes of gaseous water. 1 volume of H + 1 volume of chlorine-> 2 volumes of HCl
Mass of an electron
.0006 amu, and is estimated as 0
Rutherford Theory
a atom is composed of a very tiny nucleus, which contains positive charges and most of the mass of the atom, Very small negative electrons occupy most of the volume of the atom
mass number
the sum of the numbers of protons and neutrons in the nucleus of an atom
determining the ages of rocks and fossils
measurements of half-life make radioactive isotopes useful for
atomic mass number
the sum of the protons and neutrons in an atom
orbitals (orbital quantum #) (m)
room in analogy. space around the nucleus of an atom where 1 or 2 e-with a given energy is mostly likely to be found 90% of the time. these describe both the shape (sublevel) and the direction of motion of the e-)
Atomic and molecular motion
In solids, atoms vibrate in place with some "sway"
In liquids, atoms and molecules move past one another continuously
In gases, atoms and molecules move randomly over large distances
How many valence electrons in a chlorine atom, Cl, have a +½ spin?
The electron configuration of chlorine is 1s² 2s² 2p⁶ 3s² 3p⁵, so there is one unpaired valence electron in the p orbital. The other two p orbitals each have two electrons. One of each of the electrons has a positive spin, so three have a positive spin, and the other two have a negative spin. In the 3s orbital, one electron has a + spin while the other has a - spin. In order to occupy the same orbital, two electrons mush have opposite spins.
they are so small, it is insignificant
why aren't electrons included in the mass number?
Democritus's belief on the nature of matter
That matter was made up of particles of any shape that couldn't be divided
/ 164

Leave a Comment ({[ getComments().length ]})

Comments ({[ getComments().length ]})


{[ comment.comment ]}

View All {[ getComments().length ]} Comments
Ask a homework question - tutors are online