electronic structure and periodic properties Flashcards
when an atom absorbs energy, an electron within the atom is promoted to…
a higher energy level
orbital energy: when a hydrogen atom absorbs energy of a photon…
it converts it from a ground state to an excited state. and electron transfers to a larger orbital that is less stable
electron closer to nucleus=
stronger attraction
ionization energy
energy required to remove one electron (all has to be in gaseous state)
what is more difficult to remove
H or he+
He+ is harder to remove because more charge binds electron stronger and lowers the energy of the orbital making it more stable.
electrostatic attraction
it is more difficult to remove an electron from a positively charged species
an electron in a multi electron atom is…
attracted to the nucleus but repelled by other electrons
effects on other electrons: total number of electrons in an atom affects…
the energy levels and ionization energy
electrons with same charge
repel eachother
smallest energy possible=
most stable
1.
2 electrons, energy is
1 electron and 1 nucleus
electron to electron=
electron to nucleus=
positve
negative energy
repulsion
attraction
energy is proportional to
charge
larger distance (higher energy level)=
higher charge on nucleus=
less attraction
more attraction
force an electron feel is dependent on the..
distance from the nucleus and amount of charge!
screening
The electron-electron repulsion cancels a portion of
the attraction between the nucleus and the incoming
electron
effective nuclear charge:
electrons are only screened
by innner electrons.
smaller orbitals are more compact and screen other electrons more effectively
an electron feels an attraction called
effective nuclear charge
The higher the value of the quantum number l..
the more electrons
in that orbital are screened from the nuclear charge by electrons in
smaller, more stable orbitals.
Periodic patterns provide
information about
electron arrangements in atoms
Rules of Ground-State Configurations
No two electrons can have identical quantum numbers.
(Pauli)
3. Orbital sub-shell capacities are as follows:
s: 2 electrons, p set: 6 electrons
d set: 10 electrons, f set: 14 electrons
4. The higher the values of n, the less stable the orbital.
5. For equal n, the higher the value of l, the less stable the
orbital
The chemical properties of an atom are determined by
the electrons that are easily accessible to other atoms.
* An electron is spatially accessible when…
it occupies
one of the largest orbitals of an atom.
An electron is energetically accessible when
it
occupies one of the least stable occupied orbitals of the
atom.
* Accessible electrons are called valence electrons.
valence vs core electrons
Valence electrons participate in chemical reactions;
core electrons do not.
* Valence electrons are those of highest principle
quantum number plus those in partially filled d
and f orbitals.
* Electrons with lower n values are core electrons.
