Book: Ch. 8 Flashcards
Define: periodic law
The periodic law says that, when arranged by atomic mass, the elements exhibit a periodic recurrence of similar properties.
Define: electron configuration
The distribution of electrons within the levels and sublevels of an atom.
Define: spin quantum number (m_s)
Corresponding to the two directions of the electron’s magnetic field, this number has two possible values, +1/2 or -1/2.
What are the four quantum numbers and the possible values each can take?
Principal: n, positive integers
Angular momentum: l, integers from 0 to n - 1
Magnetic: m_l, integers from -l to 0 to +l
Spin: m_s, +1/2 or -1/2
Define: exclusion principle
No two electrons in the same atom can have the same four quantum numbers.
Per the exclusion principle, a given atomic orbital can hold a maximum of _____ electrons, which must have opposing spins.
two
Define: shielding (or screening)
Electrons shield other electrons to some extent from the nuclear charge, which produces an effective nuclear charge.
Define: effective nuclear charge (Z_eff)
The nuclear charge an electron actually experiences.
How do shielding and Z_eff relate?
As a result of shielding, effective nuclear charge is lowered. More electrons in one sublevel therefore lead to lower nuclear charge, which in turn makes electrons easier to remove.
Define: Hund’s rule
When orbitals of equal energy are available, the electron configuration of lowest energy has the maximum number of unpaired electrons with parallel spins.
Define: inner electrons (or core electrons)
The electrons of the lower energy levels starting at n - 1.
Define: outer electrons
The electrons of the highest energy level (highest n value).
Define: valence electrons
- For main group elements, just the outer electrons.
2. For transition elements, the outer electrons and the n-1 d electrons.
Atomic radius generally [increases or decreases?] down a group and [increases or decreases?] across a period.
- increases
2. decreases
Define: ionization energy (IE)
The energy required for the complete removal of 1 mol of electrons from 1 mol of gaseous atoms or ions.
Ionization energy [increases or decreases?] down a group and [increases or decreases?] across a period.
- decreases
2. increases
Define: the aufbau principle
A method for determining the electron config. Start at the beginning of the periodic table and add one proton to the nucleus and one electron to the lowest energy sublevel available and repeat until you get the element in question.
Define: electron affinity
Energy accompanying the addition of 1 mol of electrons to 1 mol of gaseous atoms or ions.
Define: isoelectronic
Ions with a noble gas configuration
Define: pseudo-noble gas configuration
If a metal atom attains the stability of empty ns and np sublevels and a filled inner (n-1)d sublevel. Refers to the (n-1)d^10 configuration.
Define: paramagnetism
A species with unpaired electrons exhibit paramagnetism: it is attracted by an external magnetic field.
Define: diamagnetism
A species with all of its electrons paired exhibits diamagnetism: it is not attracted (and is slightly repelled) by the magnetic field.
What is the relationship between a gaseous atom becoming an ion and ionization energy?
Atom (g) -> ion+ (g) + e-
Delta E = IE_1 > 0
Define: ionic radius
Measure of the size of an ion and is obtained from the distance between the nuclei of adjacent ions in a crystalline ionic compound.
Ionic size [increases or decreases] down a group, and [increases or decreases] across a period.
increases, increases
