General Chemistry Flashcards
Atomic number
number of protons in an element
Mass number
sum of element’s protons and neutrons
Isotope
Same atomic number, different mass number; differ in number of neutrons
Atomic mass
weighted average of isotopes
Bohr model of the atom
A dense, positively charged nucleus is surrounded by electrons revolving around the nucleus in orbits w/ distinct energy levels
The energy difference between energy levels in atom
quantum
Quantization
There is not an infinite rage of energy levels available to an electron; electrons can only exist at certain energy levels
Quantum mechanical model
electrons do not travel in defined orbits, but rather are localized in orbitals; orbitals defined by probability of finding electron in that region of space
Heisenberg uncertainty principle
impossible to know both electrons position and momentum at the same time
Principal quantum number (n)
Average energy of a shell
Azimuthal quantum number (l)
Describes subshells within given principal energy level (s, p, d, f); Values of 0 to n-1
Magnetic quantum number (ml)
Specifies the particular orbital within a subshell where an electron is likely to be found at a given moment in time; Values of -l to +l
Spin quantum number (ms)
Indicates spin orientation of an electron in an orbital (+ or - 1/2)
Paramagnetic
Materials have unpaired electrons that align w/ magnetic fields, attracting the material to a magnet
Diamagnetic
Materials have all paired electrons, which cannot be easily realigned; repelled by magnets
