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