Inorganic Chemistry: Periodic Table Lecture Notes

Flashcards covering the classification of elements, periodic trends, shielding effects, and physical/chemical properties as detailed in the Allen Career Institute Inorganic Chemistry lecture notes.

Periodic Table

A tool that enables the systematic study of elements and their compounds by classifying them into various groups and periods to analyze trends like ionization potential and electronegativity.

Modern Periodic Table Basis

It is based on the Bohr-Bury electronic configuration concept and the atomic number.

Shortest Period

Period $1$ ($n=1$), which contains only $2$ elements ($_{1}H$ and $_{2}He$).

Longest Period

Period $6$ ($n=6$), which contains $32$ elements ($_{55}Cs$ to $_{86}Rn$).

IUPAC Suffix for Elements $Z > 100$

The suffix is "-ium", used in names such as Unnilunium for atomic number $101$.

s-Block Elements

Elements in which the last electron enters the s-orbital ($ns^{1}$ or $ns^{2}$), consisting of $12$ total elements.

Alkali Metals

Group IA elements that react with water to form alkali.

Alkaline Earth Metals

Group IIA elements whose oxides react with water to form alkali and are found in the soil or earth.

p-Block Elements

Elements in which the last electron fills the p-orbital, with a general formula of $ns^{2} p^{1-6}$ ($n=2$ to $6$).

Inert Gases

Zero group elements with a general formula of $ns^{2} p^{6}$ (except He, which is $1s^{2}$) that are chemically inactive because their energy levels are fully filled.

d-Block Elements

Elements where the last electron enters the d-orbital of the penultimate shell; they lie between the s and p-block elements and are all metals.

Transition Elements

Elements that have partly filled d-orbitals in their neutral state or in any stable oxidation state, excluding $Zn$, $Cd$, and $Hg$, which have $d^{10}$ configurations.

f-Block Elements

Elements where the last electron enters the f-orbital, encompassing lanthanides ($Z=58$ to $71$) and actinides ($Z=90$ to $103$).

Rare Earth Elements

Lanthanides (atomic numbers $58$ to $71$) that occur in nature in low abundance.

Transuranic Elements

Elements located after uranium (atomic number $92$) in the periodic table.

Metalloids (Semi-metals)

Elements showing characteristics of both metals and non-metals, including Silicon ($Si$), Germanium ($Ge$), Arsenic ($As$), Antimony ($Sb$), and Tellurium ($Te$).

Magic Numbers

The intervals $2, 8, 8, 18, 18$, and $32$ at which elements with similar properties occur in the periodic table.

Screening Effect (Shielding Effect)

The decrease in the force of attraction exerted by the nucleus on valence electrons due to repulsive forces from inner shell electrons.

Effective Nuclear Charge ($Z_{eff}$)

The reduced nuclear charge experienced by an electron, calculated as $Z_{eff} = Z - \sigma$, where $\sigma$ is the screening constant.

Periodicity

The regular gradation in properties from top to bottom in a group and from left to right in a period caused by similar outermost shell electronic configurations.

Valency

The combining capacity of an element, based on either the number of hydrogen atoms it attaches to or its electronic configuration.

Atomic Radius

The average distance of valence shell electrons from the nucleus, often measured as half the inter-nuclear distance ($d$) between two atoms in a homoatomic molecule.

Covalent Radius

One half of the internuclear distance between two single covalently bonded atoms in a homodiatomic molecule.

Metallic Radius

One half of the internuclear distance between two closest metal atoms in a metallic crystal.

Van Der Waals Radius

Half the distance between the nuclei of two adjacent atoms belonging to two neighboring molecules of a compound in the solid state.

Transition Contraction

The contraction in size due to poor shielding of $d$ electrons, making the sizes of $Al$ and $Ga$ nearly the same.

Lanthanide Contraction

A total contraction of $13\,pm$ across the lanthanide series from $La$ ($Z=57$) to $Lu$ ($Z=71$) caused by the poor shielding of $(n-2)f$ orbitals.

Ionisation Energy (IE)

The minimum energy required to remove one mole of electrons from one mole of isolated gaseous species in its ground state.

Electron Affinity (EA)

The amount of energy released when an electron is added to the outermost shell of one mole of an isolated gaseous atom.

Electron Gain Enthalpy ($\Delta H_{EG}$)

The enthalpy change accompanying the process of adding an electron to an isolated gaseous atom; a positive EA indicates an exothermic process.

Electronegativity (EN)

A qualitative measure of the ability of an atom in a chemical compound to attract shared electrons toward itself.

Pauling Scale

An electronegativity scale where Fluorine is assigned a maximum value of $4.0$.

Mulliken's Scale

A scale where electronegativity is the average of an element's ionisation potential and electron affinity ($XM = \frac{IP + EA}{2}$).

Diagonal Relationship

The resemblance in properties between elements of the 2nd period and the 3rd period placed diagonally to them, such as $Li$ with $Mg$, $Be$ with $Al$, and $B$ with $Si$.

Amphoteric Oxides

Oxides that exhibit both acidic and basic properties, such as $Al_{2}O_{3}$, $ZnO$, $SnO$, and $PbO_{2}$.

Neutral Oxides

Oxides that show no acidic or basic properties, including $CO$, $H_{2}O$, $NO$, and $N_{2}O$.