Electronic structure Flashcards
what is the uncertainty principle
you can never know both the exact location and velocity of a subatomic particle at the same time
what are ionization energies
ionization energies are measures of the amount of energy needed to remove electrons from atoms (or ions)
what is the definition for first ionization energy
the energy required to remove one mole of electrons from one mole of gaseous atoms to for one mole of gaseous psositive ions
why are ionization energies always positive
because electrons and protons attract one another so energy must be added to the system to pull the electron away
why does an atom with a high nuclear charge have a high ionization energy
the greater the pull of the nucleus the harder it will be to pull an electron away (more energy required) so higher ionization energy
what do ionization trends give evidence for
electrons being in shells and subshells
what is electron affinity
the amount of energy needed to add electrons to atoms/ions
what is the definition of the first electron affinity
the energy required to add one mole of electrons to one mole of a gaseous atom to form one mole of gaseous negative ions
why is first electron affinities negative
indicates energy is released on the addition of the electron
the more negative the electron affinity, the more stable the negative ion that is formed
what is the trend of atomic size
increases down a group, decreases across a period
what is the trend of first ionization energy
decreases down a group and increases across a period
what is the trend of first electron affinity
becomes less negative down a group and become more negative across a period
what is an orbital
a region in space where there is a given (usually 95%) probability of finding a particular electron
cannot specify the definite or exact position of an electron in an atom
what do quantum numbers do
identify the various energy levels available with the atom in which the electrons can reside
they are identification numbers “address” for each electron in an atom
- they specify the position (or location) of an electron in an atom
- predict the direction of spin or rotation of the electron
- determine the energy and angular momentum of an electron
name the four quantum numbers that are required to specify the character of an electron
- principal quantum numbers (n)
- azimuthal or subsidaiart quantum numbers (l)
- magnetic quantum numbers (m)
- spin quantum numbers (s)
in poly-electron atoms what are principal energy levels called and referred to by
they are called shells and referred to by letter - K, L, M….
what principle quantum number do principal energy levels correspond to
the principal quantum number ‘n’