Studied by 14 peopleAtom
the smallest piece of an element that still represents that element
electron
A particle with one negative charge (-1)
Nucelus
where most of an atom's mass and positive charge are centered. The nucleus in the center of an atom.
Proton
an atomic particle with a positive charge (1+).
Neutron
a particle that exists the nucleus of an atom
electron cloud
an area around an atomic nucleus where an electron is most likely to be located.
Atomic Number
The number of protons in an atom of an element.
Isotopes
atoms of the same element with different numbers of neutrons.
Mass Number
the sum of the number of protons and neutrons in an atom.
Average Atomic Mass
mass of the element isotopes, weighted accordingly to the abundance of each isotope.
Radioactive
elements that spontaneously emit radiation
Nuclear Decay
a process that occurs when an unstable atomic nucleus changes into another more stable nucleus using radiation.
aplha decay
an unstable atom shoots off alpha particles to become stable.
Beta Decay (+)
Proton becomes a neutron + an electron (positron).
Beta Decay (-)
Neutron becomes a proton + electron.
What is the result of beta decay?
Mass does not change but, a new atom forms because atomic number has changed.
What is the result of alpha decay?
the atom becomes a different element.
Gamma Decay
A nucleus gives off [this kind] radiation to become more stable
Gamma rays are... (not matter)
energy
What is the result of gamma decay?
atomic number does not change.
Who intoduced the term "atomos"?
Democritus
Who coined the term "atom"?
John Dalton.
What was Dalton's atomic theory?
(1)All matter is made of atoms that can't be divided, created, or destroyed. (2)during a chemical reaction, atoms of one element can't be converted to another element (3)atoms of one element are identical to each other but different from those of other elements (4)atoms combine in specific ratios (5)All of these (6)none of these
(5)
JJ Thomson invented what model?
Plum Pudding Model
What experiment did JJ Thomson do?
cathode ray tube experiment
What did JJ Thomson learn/discover from his experiment?
negatively charged atoms (electrons)
What did JJ Thomson's model look like?
A sphere of positive charge with electrons embedded in the sphere. He thought that the negatively charged electrons were balanced out by a positively charged particle.
Ernest Rutherford did what experiment?
Gold foil
Rutherford was a student of JJ Thomson. (True or False?)
True
What did Rutherford discover?
positively charged nucleus. (Protons and nuecleus). Atoms are largely EMPTY SPACE.
What did Neils Bohr do?
Discovered some important things with electrons. Proved the Plum Pudding Model partially correct.
What did Neils Bohr think?
Electrons orbits (he thought the orbits were circular like planetary orbits -that was proven incorrect later).
Was Neils Bohr correct with his idea of electrons orbit?
No. Though he was slightly right, electrons move, but not in circular orbit.
Erwin Schrodinger did what?
Crated the quantum model of the atom. Had the cat thought experiment (Quantum Superstition). Electron energy levels. Electron cloud.
James Chadwick discovered what?
neutrons
Why did it take so long to discover the neutron?
The neutron has no charge. It could not be detected. It was discovered because of unexplained mass.
What is the modern atomic model?
Atoms have two parts: Nucleus with protons and neutrons and electrons in the electron cloud. electrons travel with such speed that you can't know where they are at any given point. (They travel like waves) Atoms are mostly empty space.
What is quarks?
Quarks are the things that make up protons and neutrons.
has anyone ever seen a qaurk?
no.
atomic number
True or False: Carbon will always have 6 protons but can have different amounts of neutrons.
true.
Ion
an atom that is no longer neutral because it has gained or lost electrons.
Are ions charged?
yes, because they have unequal amounts of protons and electrons.
If an ion loses electron(s), what is its charge?
postive
If an ion gains electron(s), what is its charge?
negative
True or False: Salt is made up of ions.
true
The result of Thomson's experiments led him to conclude that
cathode rays are made up of negatively charged particiles.
Which Scientist showed that most of the mass and positive charge of an atom is concentrated in its center?
Rutherford
The Bohr model of the atom proposed that electrons
move in circular orbits around the nucleus
What is quark?
a kind of particle that makes up protons and neutrons
_________________ have charges of 1-.
electrons
_________________________ and protons have the same relative mass.
neutrons.
The number of __________________ in an atom of an element is element's atomic number.
protons
Carbon-12 and Carbon-13 are isotopes, so they have differnt numbers of __________________.
neutrons
The mass number of an atom can be determined by adding the number of __________________ and the number of neutrons.
protons.
An alpha particle consists of
2 protons and 2 neutrons
a positively charged ion is formed when
an electron is lost
beta particle is
a highly charged electron.
Note
Flashcard