Early Theories
Not-cuttable.
What is "Atomos"?
Not a scientist; invented the term "atomos".
Who was Democritus?
The deflection of a cathode-ray from a negative electrode is evidence for the existence of these.
What are electrons?
The smallest component of an element having the chemical properties of the element.
What is an atom?
The current model of the atom.
What is the electron-cloud model?
Matter is composed of atoms; the smallest, indivisible particle of matter that can combine in simple, whole-number ratios to form compounds.
What is the "Billiard Ball" model?
Derived the first scientific atomic theory based on experimental evidence.
Who was John Dalton?
The ability of a cathode ray to move a paddle wheel is evidence for this property.
What is the mass of an electron?
The smallest subatomic particle of matter that carries a negative charge.
What is an electron?
Occurs when electrons absorb the exact amount of energy equal to Ehigher orbit - Elower orbit.
What are quantum leaps.
A mass of positive charge with electrons embedded throughout.
What is the "Plum Pudding" model?
Discovered the quantized nature of energy; derived the equation E = hv.
Who is Max Planck?
Positive particles emitted from a radioactive source that carries a 2- charge.
What are alpha particles?
A particle of electromagnetic radiation; carries an amount of energy equal to hv.
What is a photon?
A 3-d region of space where there is a 90% probability of locating an electron.
What is an orbital?
All of the positive "mass" of the atom is concentrated in a very small, dense center if an atom with electrons moving outside of the center in a vast region of empty space.
What is the "Nuclear Model"?
Discovered the source of any form of EMR; quantum leaps from higher orbits to lower orbits.
Who is Niels Bohr?
One in 8000 positively-charged particles would deflect nearly back at their source instead of passing through a thin sheet of gold-foil is evidence for the existence of this?
What is the nucleus?
A large subatomic particle found in the nucleus that carries a charge equal in magnitude to the electron.
What is a proton?
Energy level closest to the nucleus.
What is n=1?
A changing region of probability in locating this particle.
What is an electron wave?
Proposed the wave-nature of the electron.
Who is Louis de Broglie?
Evidence that electrons exhibit wave behavior.
What is a diffraction (or interference) pattern?
Electromagnetic energy passing through a pinhole opening exhibits this.
What is wave behavior?
Developed by Schrodinger; Describes the probability of locating any electron in any atom.
What are the quantum numbers?