Chapter 4 Flashcards
The smallest unit of an element that maintains the properties of that element
Atom
A subatomic particle that has a negative charge
Electron
In physical science, and atom’s central region , which is made of protons and neutrons
Nucleus
A region around the nucleus of an atom where electrons are likely to be found
Electron Cloud
He began the atomic theory. He thought that matter is composed of atoms. He used observations for his experiments.
Democritus
He though you could never end up with a particle that couldn’t be cut.
Aristole
He suggested that elements combine in certain proportions. He said atoms can’t be created destroyed, or divided. He Said atoms of the same element are alike. He said atoms join with other atoms to make new substances.
Dalton
He discovered small particles in an atom called electrons. He use a cathode-ray and showed that a positively charged plate attracted the beam. He stated that electrons are negatively charged and are present in every kind of atom.
Thompson
He aimed a beam of small, positively charged particles at a thin sheet of gold foil. He put coating behind the foil. The coating glowed after being hit by the particles. When the particles hit the gold foil some bounced back. He is the one who found discovered the nucleus.
Rutherford
He studied the way atoms react to light. He is model there are no paths before one level to another. He found that electrons can jump from one path to another.
Bohr
A subatomic particle with a positive charge
Proton
A unit of mass that describes the mass of an atom
Atomic Mass Unit
A subatomic particle found in the nucleus with no charge
Neutrons
The number of protons in an atom
Atomic Number
An atom that has the same number of protons as other atoms of the same element do but that has a different number of neutrons
Isotope
