General Chemistry Chapter 7: Periodic Properties of the Elements

Comprehensive vocabulary flashcards covering periodic trends, effective nuclear charge, atomic and ionic radii, ionization energy, electron affinity, electronegativity, and group chemistry from Chapter 7.

Periodic Law

The principle that arranging chemical elements in order of increasing atomic mass causes similar chemical and physical properties to recur periodically across columns.

Coulomb's Law

A law governing the electrostatic interaction energy between charged particles, stating that potential energy ($E$) is directly proportional to charge magnitude ($q_1 q_2$) and inversely proportional to the separation distance ($r$): $E = \frac{1}{4\pi\varepsilon_0} \frac{q_1 q_2}{r}$.

Effective Nuclear Charge ($Z_{\text{eff}}$)

The net positive nuclear charge experienced by an electron in a multielectron atom, reduced from the actual nuclear charge ($Z$) by electron shielding from inner core electrons via screening constant ($S$).

Electron Shielding

The repulsive interaction between inner core electrons and valence electrons in an atom, which reduces the total electrostatic attraction that valence electrons feel toward the positively charged nucleus.

Electron Penetration

The ability of an outer electron in a multielectron atom to penetrate into the region of inner electron density, bringing it closer to the nucleus and lowering its sublevel energy relative to less penetrating sublevels.

Covalent Radius (Bonding Atomic Radius)

Half the distance between the nuclei of two identical atoms joined by a chemical bond, generally determined experimentally through X-ray crystallography (such as $\frac{228\,\text{pm}}{2} = 114\,\text{pm}$ for bromine).

Van der Waals Radius (Nonbonding Atomic Radius)

Half of the minimum distance between adjacent, nonbonded atomic nuclei in a solid lattice of an element, representing the atomic boundary when atoms collide without bonding.

Isoelectronic Series

A set of atoms and ions sharing an identical electron configuration and equal total number of electrons, such as $N^{3-}$, $O^{2-}$, $F^{-}$, $Ne$, $Na^{+}$, $Mg^{2+}$, and $Al^{3+}$.

Ionization Energy (IE)

The energy required to remove an electron from a gaseous atom or ion in its ground state, which is always an endothermic process ($M_{(g)} \rightarrow M^{+}_{(g)} + e^{-}$, with $h\nu = \phi$ when kinetic energy equals zero).

Core Electron Ionization Jump

A dramatic, sharp spike in successive ionization energy that occurs after all valence electrons have been removed and an electron must be pulled from an inner core noble gas configuration.

Electron Affinity (EA)

The energy change associated with adding an electron to a neutral gaseous atom to form an anion ($M_{(g)} + e^{-} \rightarrow M^{-}_{(g)}$), which is generally exothermic for the first electron and always endothermic for subsequent electrons.

Metallic Character

A measure of how readily an element displays metallic traits such as malleability, ductility, lustrous appearance, high electrical and thermal conductivity, and the ability to readily lose electrons to form cations.

Allred-Rochow Electronegativity

An electronegativity scale that calculates the electrostatic attractive force experienced by valence electrons using effective nuclear charge ($Z_{\text{eff}}$) and covalent radius ($r$ in Angstroms): $\chi = \frac{0.359 \cdot Z_{\text{eff}}}{r^2} + 0.744$.

Alkali Metals

Group 1A metals characterized by low density, softness, low melting points, single $ns^1$ valence configurations, low ionization energies, and vigorous, highly exothermic reactions with water.

Alkaline Earth Metals

Group 2A metals with an $ns^2$ valence electron configuration that are harder, denser, and have higher melting points and ionization energies than alkali metals, with reactivity toward water increasing down the group.

Halogens

Reactive Group 7A nonmetals with an $ns^2 np^5$ valence configuration that possess very high electron affinities, act as strong oxidizing agents, form soluble salts with metals, and produce acids of the form $HX$ when reacted with hydrogen.

Noble Gases

Chemically unreactive Group 8A nonmetals with completely filled valence shells ($1s^2$ or $ns^2 np^6$), unusually high first ionization energies, and endothermic electron affinities ($EA > 0$).

Itai-Itai Disease

A severe cadmium poisoning outbreak in Toyama Prefecture, Japan, caused by heavy metal runoff into rivers and rice paddies; toxic $Cd^{2+}$ mimics $Ca^{2+}$ due to their similar ionic radii ($\approx 140\,\text{pm}$), leading to osteomalacia and kidney failure.