Chapter 8 Flashcards
actinides
the Period 7 elements that constitute the second inner transition series (5f block), which includes thorium (Th; Z = 90) through lawrencium (Lr; Z = 103)
amphoteric
able to act as either an acid or a base
atomic size
a measure of how closely one atom lies next to another, determined from the distances between nuclei of adjacent atoms
aufbau principle
the conceptual approach for building up atoms by adding one proton at a time to the nucleus and one electron to the lowest energy sublevel that is available, to obtain the ground-state electron configurations of the elements
covalent radius
one-half the shortest distance between nuclei of identical covalently bonded atoms
dimagnetism
the tendency of a species not to be attracted (or to be slightly repelled) by a magnetic field as a result of its electrons being paired
effective nuclear charge (Zeff)
the nuclear charge an electron actually experiences as a result of shielding effects due to the presence of other electrons
electron affinity (EA)
the energy change (in kJ) accompanying the addition of 1 mol of electrons to 1 mol of gaseous atoms or ions.
electron configuration
the distribution of electrons within the levels and sublevels of the atoms of an element; also the notation for such a distribution
Hund’s rule
a principle stating that, when orbitals of equal energy are available, the electron configuration of lowest energy has the maximum number of unpaired electrons with parallel spins
inner (core) electrons
electrons that fill all the energy levels of an atom except the valence level; electrons also present in atoms of the previous noble gas and any completed transition series
inner transition elements
the elements of the periodic table in which the seven inner f orbitals are being filled; the lanthanides and the actinides
ionic radius
the size of an ion as measured by the distance between the nuclei of adjacent ions in a crystalline ionic compound
ionization energy (IE)
the energy (in kJ) required for complete removal of 1 mol of electrons from 1 mol of gaseous atoms or ions
isoelectronic
having the same number and configuration of electrons as another species
lanthanides
the Period 6 (4f) series of inner transition elements, which includes cerium (Ce; Z = 58) through lutetium (Lu; Z = 71)
metallic radius
one-half the shortest distance between the nuclei of adjacent individual atoms in a crystal of an element
orbital diagram
a depiction of orbital occupancy in terms of electron number and spin shown by means of arrows in a series of small boxes or on a series of short lines
outer electrons
electrons that occupy the highest energy level (highest n value) and are, on average, farthest from the nucleus
paramagnetism
the tendency of a species with unpaired electrons to be attracted by an external magnetic field
pauli exclusion principle
a principle developed by Wolfgang Pauli stating that no two electrons in an atom can have the same set of four quantum numbers. the principle arises from the fact that an orbital has a maximum occupancy of two electrons and their spins are paired
penetration
the phenomenon in which an outer electron moves through the region occupied by the core electrons to spend part of its time closer to the nucleus; penetration increases the average effective nuclear charge for that electron
periodic law
a law stating that, when the elements are arranged by atomic mass, they exhibit a periodic recurrence of properties
pseudo-noble gas configuration
the (n − 1)d10 configuration of a p-block metal ion that has an empty outer energy level
shielding
the ability of other electrons, especially those occupying inner orbitals, to lessen the nuclear attraction for an outer electron
spin quantum number
a number, either +1/2 or -1/2 that indicates the direction of electron spin
transition elements
an element that occupies the d block or the f block (inner transition element) of the periodic table
