Chemistry-History of the Atom
in Rutherford's experiments, most of the particles ?
passed through the foil
Rutherford concluded that atoms have a massive central region with a ?
positive charge
bohr model
Bohr
came up with the idea that electrons emit light by jumping orbits
Bohr
discovered that electrons can move up an energy level if given enough energy
Bohr
discovered that electrons will travel around the atom in discrete energy levels and that electrons only exist on these levels, never in between levels
Bohr
explained that outer orbits in an atom could hold more electrons than the inner obrits
Bohr
quantum of energy is the exact amount of energy for an electron to move up a level
Bohr
chemists observing that mass is neither created nor destroyed in a chemical reaction demonstrates the scientific law of?
conservation of mass
1766-1844
Dalton
all matter is composed of atoms, atoms cannot be created or destroyed, all atoms of the same element are identical in size, mass and properties, chemical reactions occur when atoms are rearranged, compounds are formed by the combination of 2 or more different kinds of atoms
Dalton
developed the atomic theory
Dalton
460-370 BC
Democritus
described an atom as uncuttable, invisible and indestructable
Democritus
first person to come up with the idea of the atom
Democritus
his idea lacked evidence and was based on reason and he did no experiements
Democritus
said atoms are basic elements from which all matter is made
Democritus
said everything is composed of small atoms moving in a void
Democritus
said some atoms are round, pointy, oily, have hooks, etc to account for their properties
Democritus
candy models?
Democritus- miscellaneous hard candies, Dalton- sweet tarts, Thomson- choc chip cookie, Rutherford- tootsie pop, Bohr-gobstoppers, Heisenberg-ferrero chocolate
said that one of the implications of electrons behaving like waves is that you can not know both the speed and position of an electron at the same time
Heisenberg's uncertainty principle
concluded that all positive charges were centralized, while negative electrons orbited the nucleus
Rutherford
discovered that an atom is made up of mostly open space
Rutherford
discovered the positively charged part of the atom called a proton
Rutherford
experiments helped to identify the nucleus of the atom
Rutherford
used the gold foil experiment to discover the modern model of an atom
Rutherford
1856-1949
Thomson
discovered isotopes
Thomson
discovered that the atom could be divided
Thomson
discovered the negatively charged part of an atom called an electron
Thomson
experimented by testing and studying the nature of electric discharge in a high vacume cathode-ray tube (which led to the discovery of the electron)
Thomson
plum pudding model (electrons in a soup of positive charges)
Thomson
Rutherford called the region that deflected alpha particles?
a nucleus
in the gold foil experiment, Rutherford concluded that particles were striking ?
a tiny region of positive charge
Dalton's atomic theory agrees with the modern atomic theory except for the statement that?
all atoms of the same element have the same mass
how has Dalton's atomic theory been shown to be incorrect?
atoms can be split into subatomic particles
in Rutherford's experiment, particles were used to ?
bombard thin metal foil
John Dalton thought that atoms ?
cannot be broken down further
In Thomson's experiment, the deflection of cathode ray tubes was the evidence of the ?
charged nature of electrons
atoms of the same element may have different?
masses
law of conservation of mass includes that?
matter is composed of atoms
experiments with cathode rays being deflected by a magnetic field show that cathode rays are composed of particles that are ?
negatively charged
cathode rays are composed of particles known as?
neutrons
from Rutherford's experiment with foil he concluded that the alpha particles
repelled by densely packed regions of positive charge
when an electric current passed through a glass tube, it caused the surface of the tube directly across from the the cathode to glow, scientists concluded that?
the particles of the beam were negatively charged