Download The Modern Nuclear Atom

• “All atoms of the same element contain the same number of
protons and electrons, but may have different numbers of
neutrons.”
• Isotopes = atoms with the same number of electrons
and protons but different numbers of neutrons.
• Atomic number = number of protons
• Mass number = the sum of the protons and neutrons in
an atom’s nucleus
• Show the element symbol, mass number
and atomic number
• Scientists discovered the relationship between matter
and light
• Max Planck suggested that objects emit energy
in a specific quantity, called a quantum
• Albert Einstein
• Proposed a Hydrogen-atom model in 1913
• Electrons circle the nucleus in a specific orbit
worked for the Hydrogen
atom
1924
•Electrons have specific
wavelengths
•They can interfere with
each other
electrons could
be detected
•The Heisenberg Uncertainty
Principle = it is impossible to
determine both the position
and the velocity of an electron
• Developed a mathematic
equation that predicted the
behavior or electrons in 1926.
•The Quantum Atomic Theory
mathematically describes the
properties of electrons
• Probability model
• Orbitals = 3-dimensional regions around the
nucleus where an electron is most likely to be
found
• Used to describe the properties of electron orbitals
Four quantum numbers:
• Principle
(n) = the main energy level
• Angular momentum
(l) = the shape of
the orbital (s, p, d, or f )
• Magnetic
(m) = the orientation of an
orbital
• Spin
(+ or -) = the spin direction of an
electron