Atomic Structure, Periodic Table, Elements Flashcards
Atomic number
The number of protons in nucleus of atoms
Identifies element, no 2 elements have same atomic numbers
Determined by Henry Moseley
Mass number
The sum of number of protons & neutrons in nucleus
Isotopes
Atoms of same element that have same atomic numbers but different atomic masses
Same number of protons & electrons but different numbers of neutrons
Average atomic mass
Weighted average of atomic masses of naturally occurring isotopes of an element
Depends on mass & relative abundance of each elements isotopes
Valence electrons
The electrons found in the outermost energy level
Core electrons
All electrons but valence electrons
Valence of atom
Absolute number of electrons gained, lost, or borrowed
Spectroscope
Instrument used to analyse light by separating it into its component wavelengths
Mass spectroscopy
Separates isotopes of same element based of differences in their mass
Principal quantum number
Average distance of orbital from nucleus
Refers to principal energy levels
1,2,3,4…
Angular momentum quantum number
Refers to shape of orbital
S,p,d,f
Magnetic quantum number
Determines number of orbitals & their orientation within subshell S = 1 space oriented orbital p = 3 d = 5 f = 7
Spin Quantum Number
Refers to direction of electron spin
Either downward or upward
Pauli Exclusion Principle
Each electron orbital of an atom can only have 2 electrons, with opposite spins - not same 4 quantum numbers
Aufbau Principle
An electron occupies the lowest energy orbital that can receive it
Hund’s Rule
Electrons fills orbitals one at time, pairing will occur with addition of 1 more electron to each orbital
Transition Elements
The elements involved with the filling a d-sublevel with electrons after 2 electrons are in the s-sublevel of next principal level
Periodic Law
The chemical properties of elements vary periodically with their atomic numbers
Electronegativity
A number that measures the relative strength with which the atoms of the element attract valence electrons in a chemical bond
The higher the number, the greater the attraction
Ionisation
The removal of one or more electrons
First ionisation energy
The energy needed to remove 1 outer electron from its atom
Half-life
The time it takes for 1/2 of radioactive nuclei to decay
Transmutation
Changing 1 element into another (by change in protons)
Either by radioactive disintegration or bombardment of nuclei of substance with particles from particle accelerator
Radioactive dating
Determination of the age of a substance with bits of organic material trapped in them
Nuclear reaction
Any reaction involving a change in nuclear structure
Nuclear fission reaction
The splitting of a heavy nucleus into 2/more lighter nuclei
Nuclear fusion reaction
The combination of very light nuclei to make a heavier nuclei
Nucleons
Protons & neutrons in the nucleus
Ground State
Lowest energy state available to the electron
Excited State
Any level higher than the ground state
Lyman Series (ultraviolet)
The emission that occur when an electron cascades from a level higher than the first level down to n=1
Balmer Series (visible)
The emissions that occur when an electron cascades from a level higher than first level down to n=2
Paschen Series (infrared)
The emissions that occur when an electron cascades from a level higher than the first level down to n=3
Uncertainty Principle
The position & momentum of a particle cannot be accurately measured at the same time
Photon
A quantum of electromagnetic waves; wave-packets of EM waves that carry energy
Atomic Spectra
The range of frequency/wavelengths of EM waves emitted/absorbed during transitions of electrons between energy levels within an atom
Alpha Decay
Emits alpha particle to get more stable nucleus, same composition as Helium nucleus
Beta Decay
Emits an electron from nucleus
Gamma Decay
Protons & neutrons reconfigure themselves & so release energy in the form of high wavelength electromagnetic wave (gamma ray)
Radon
Gas produced from spontaneous disintegration of nuclei of radioactive elements
Spectra
An array of entities, as light waves or particles, arranged in accordance with magnitude of a common physical property, as wavelength or mass
