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Flashcards: Chemistry definition - Leaving Cert
Energy level
Fixed energy value an electron in an atom may have
Ground state
Electron occupy the lowest available energy level
Excited state
Electrons occupy higher energy level than the ground state
Heisenberg's uncertainty principle
Impossible to measure both velocity and position of an electron
Orbital
Volume around the nucleus high chance of finding electron
Sublevel
Subdivision of main energy level with one or more orbitals
Elements
Substance that can't be split into simpler substances by chemical means
Mass number
Sum of number of protons and neutron in the nucleus
Isotope
Atom with same atomic number but different mass number due to neutrons
Relative atomic mass
Average sum of mass of isotope relative to one 12th a carbon 12 atom
Mass spectrometry
In a electromagnetic field charged particles are deflected according to their mass
Aufbau principle
In an electron configuration electrons always occupy the lowest available energy level
Compound
Substances made of different elements combined by chemical means
Ions
Charged atom
Ionic bond
Attraction between oppositely charges ions with
Transition metal
Metal that forms an ion with a partially filled d sublevel
Molecule
A group of atoms joined together
Sigma bond
Head on overlap of orbitals
Pi bond
Sideways overlap of p orbitals