Atomic Structure Flashcards
Atom
Basic building block of matter, consist of protons, electrons, and neutrons
Protons
+1
1.0073 amu
Neutron
No charge, slightly heavier than a proton
Electron
-1
1/1837 mass of proton or neutron
Valence electrons
Electrons farthest away from nucleus that participate in bonding
Orbital
Region around nucleus where electron is likely to be found
Each has unique assignment for n, l, and m(l) quantum numbers
Atomic Number
Number of protons
Mass Number
Protons + Neutrons
Nucleus
Dense, positively charged atomic center that contains protons and neutrons
Atomic Mass Unit
1/12 of Carbon-12 atom mass
Atomic Weight
Average mass of all naturally occurring isotopes of a given element, measured in amu
Avogadro’s Number
6.022 X 10^23 atoms/ mol
Isotopes
Same atomic number, but different neutron number
Bohr Model
Atomic model where electrons located in discrete circular orbits around nucleus, with electrostatic force acting as centripetal force
What does emission give rise to and how is it useful?
Emission gives rise to fluorescence and the unique atomic emission spectra could be used to identify an element
Quantum Mechanics
Study of physics at atomic level with discrete levels of energy
Atomic Emission Spectra
Discontinuous spectra of lit produced when electrons emit photons of certain frequencies as they return to their ground states
Atomic Absorption Spectra
The spectrum of certain absorbed light wavelengths corresponding to the energy electrons require to jump to the next energy level
What is the basis for color in compounds?
Absorption
Balmer Series
Set of spectral lines that appear in visible light region when hydrogen atom undergoes transition from energy levels n > 2 to n = 2
Lyman Series
Set of spectral lines that appear in UV region when hydrogen atom undergoes a transition from energy levels n > 1 to n = 1
Heisenberg Uncertainty Principle
Impossible to determine with perfect accuracy the exact momentum and position of orbiting electron simultaneously
Quantum Number
Set of four numbers used to describe electrons energy state
Photon
Unit of energy in the form of light equal to hf
Pauli Exclusion Principe
No two electrons in the same atom can possess the same set of four quantum numbers
Principal Quantum Number
It is any positive integer value and it describes an electron’s energy value
Max number of electrons in energy level n is 2n^2, where the difference in energy between adjacent shells decreases as distance from nucleus increases
Azimuthal (Angular Momentum) Quantum Number
Refers to the subshells, ranges from 0 to n-1
l = 0, 1, 2, 3 ===> s, p, d, f
Max number of electrons in a subshell = 4l + 2
Magnetic Quantum Number
Specific Region within a subshell where highly likely to find an electron, ranging from -l to l, including 0
Spin Quantum Number
-1/2 or + 1/2
What are the four quantum numbers?
Principal Quantum Number
Azimuthal Quantum Number
Magnetic Quantum Number
Spin Quantum Number
Electron Configuration
Patterned order by which electrons fill subshells and energy levels in an atom
Aufbau Principle
Electrons fill an atom in order of increasing energy level
Hund’s Rule
Electrons will first fill equal energy orbital of subshell unpaired with parallel spins before coupling with other electrons of opposite spins in same orbital to maximize number of half-filled orbitals, allowing for most stable electron distribution
Paschen Series
Set of spectral lines resulting when a hydrogen atom undergoes transition from energy levels n > 4 to n =3
Isoelectronic
Two different elements with same electron configuration
Paramagnetic
Atom or substance with unpaired electrons and attracted by a magnet
Diamagnetic
Atom or substance with no unpaired electrons and repelled by a magnet
Pfund Series
Set of spectral lines resulting when a hydrogen atom undergoes a transition from energy levels n > 5 to n = 5
