Ch 8 - Periodic Properties of the Elements Flashcards
Periodic Property
a property of an element that is predictable based on the elements position within the periodic table.
Dmitri Mendeleev
credited for the creation of the modern periodic table.
Periodic law
when elements are arranged in order of increasing mass(later corrected to atomic number not mass) certain properties recur periodically.
Electron Configuration
shows the particular orbitals that electrons occupy for an atom.
Ground State
the lowest energy state of an electron.
Orbital Diagram
symbolizes the electron as an arrow and the orbital as a box(half an arrow up and half and arrow down = 2 electrons with different spins)
Pauli Exclusion princple
Wolfgang Pauli.
No two electrons in an atom can have the same four quantum numbers(m,n,ml,and ms)
If two electrons are in the same orbital then they have different spins(+1/2 and -1/2 for ms)
Degenerate
in a hydrogen atom the empty energy levels have the same energy.
Not degenerate
in multi electron atoms the energy of electrons in orbits within a principal level depends on the value of “l”.
Generally the lower the value of “l” the lower the level of E.
E(s orbital) < E(p orbital) < E (d orbital) < E (f orbital)
Coulombs law
the potential energy(E) of two charged particles depends on their charges(q1 and q2) and on their separation(r).
E = (1/(4pie(e0)))((q1q2)/r)
e0 = 8.85 * 1-^-12 C^2/(J)(m)
Shielding
the repulsion of one electron by other electrons that screens or shields that electron from the full effects of the nuclear charge.
effective nuclear charge(Zeff)
the difference between the nucleus and other electrons in the way of an electron feeling the charge from the nucleus.
3+ and 2-(shielding) = a net 1+ charge on an outer electron.
**Radius is constant for non main group elements because of shielding.
Penetration
Occurs when an outer electron enters into the region occupied by the inner electrons and experiences a greater nuclear charge(based on less shielding from inner electrons). Subsequently the electron that penetrated has a lower energy(closer to nucleus)
Paramagnetism
unpaired electrons aligned in the same direction.
Magnetic field
Diamagnetism
paired electrons.
No magnetic field
Zeff
basically just the number of valence electrons = charge experienced
Size of an atom
Radius increases down a column
Radius increase from right to left across a period.
Rb larger. He Smaller.
Ionization Energy
minimum amount of energy needed to remove an electron from an atom.
More energy from left to right on a period.
More energy from bottom to town of a colum.
He requires most energy to ionize.
Cs requires least energy.
ALWAYS ENDOTHERMIC(electron needs more energy to leave atom)
Electron Addinity
the ability to gain an electron.
Generally, more negative(more energy required) from left to right.(halogens have highest EA)
5A lower EA than expected(extra electron must pair)
2A and 8A tend to have low EA(electron goes to higher energy level)
mostly EXOTHERMIC(take energy to add electrons)
Metallic Character
how closely an elements properties match the ideal properties of a metal.
malleable, ductile, easy to ionize, and good conductors.
decreases from left to right.
Increases down a column.
Size of ions
Cations: smaller than parent(less - to + = closer to nucleus)
Anion: larger than parent(more - to + = farther from nucleus)
Lattice Energy
the energy required to completely separate a mole of a solid ionic compound into its gaseous ions.
Crystal lattice
maximizes the attractions between cations and anions, leading to the most stable arrangement.
