What was the Greek word that "atom" derived from?
Whose model is a sphere that can't be split?
Democritus' atomic model
What were Aristotle's primary elements?
fire, earth, water, air
What were Aristotle's secondary elements?
hot, cold, dry, wet
What was the first point of Dalton's atomic theory?
all matter is made of atoms
What was the second point of Dalton's atomic theory?
atoms of a given element are identical in size, mass and chemical properties
What was the third point of Dalton's atomic theory?
atoms of different elements have different masses and chemical properties
What is an electron?
subatomic particle that carries a negative energy
Who discovered the electron?
When was the electron discovered?
What was a cathode ray tube?
vacuum tube containing electron gun
What was J.J Thomson's atomic model?
What is radioactivity?
particles which are emitted from nuclei as a result of nuclear instability
Who discovered radioactivity?
When was radioactivity discovered?
What were the radioactive elements that Pierre and Marie Curie first isolated?
polonium and radium
What was the effect of the discovery of radioactivity on understanding of atoms?
atoms are neither indivisible nor immutable
What is alpha radioactive decay?
when the nucleus has too many protons which causes excessive repulsion
What is beta radioactive decay?
when the neutron to proton ratio is too great in the nucleus and causes instability
What is gamma radioactive decay?
occurs when the nucleus is too high in energy
The nucleus of an atom is...
very dense region in the center of atom consisting of nucleons
Who discovered the nucleus?
When was the nucleus discovered?
What is a proton?
subatomic particle with an electric charge
Who discovered the proton?
When was the proton discovered?
What is a photon?
elementary particle; the quantum of electromagnetic interaction and basic unit of light
What are the causes of an electron to jump to a larger orbit or to drop to a smaller orbit?
larger orbit: add a photon to the atom
smaller orbit: get rid of a photon from the atom
What is a neutron?
subatomic particle with no electric charge and a mass slightly larger than a proton
Who discovered the neutron?
When was the neutron was discovered?
The area where most of the mass of an atom is located is...
What is the electron cloud model?
modern model of the atom
What is atomic orbit?
concept of Bohr's atomic theory
What is atomic orbital?
a mathematical function that describes the wave-like behavior of either one electron or a pair of electrons in an atom