The amount of time it takes for half of a radioactive substance to decay
half-life
Alchemists tried to produce this from other materials
gold
atoms of the same element but with different numbers of neutrons are
Isotope
A high energy type of electromagnetic radiation
Gamma Ray
means splitting apart
Fission
A fast moving electron
Beta particle.
Identical to the nucleus of a helium atom.
Alpha particle
Consists of a proton and an electron.
Hydrogen 1
When two protons repel each other we say that the _____ is working
Electrical force.
Can be used besides uranium to make atomic bombs and nuclear power plant fuel.
Plutonium
Happens when two small atoms collide and combine to become a bigger atom.
Fusion
Democritus
Democritus came up with the idea that all matter contains atoms. He reasoned that atoms were the smallest part of matter, and could not be broken down further.
Dalton
John Dalton was one of the first to develop an atomic model. He thought that the atom was the smallest possible component of matter.
J.J. Thompson
Discovered the electron.
Rutherford
Found the atom.
Law of conservation of mass
a fundamental principle of classical physics that matter cannot be created or destroyed in an isolated system
What is made in the upper atmosphere when a neutron collides with a nitrogen atom.
Carbon 14
Consists of two protons and two neutrons.
Alpha Particle
Two of these combine with an alpha particle to make helium gas.
Electron
The amount of a fissionable material that it takes to get a chain reaction going.
Critical mass
Can go through paper but can be stopped by aluminum foil or thin glass