S-block Elements Lecture Notes

A collection of vocabulary-style flashcards covering Group 1 (Alkali Metals) and Group 2 (Alkaline Earth Metals), including electronic configurations, trends, reactions, specific compounds, and biological importance.

S-block element

An element in which the last electron enters the S-subshell.

Alkali metal electronic configuration

$$[\text{Noble gas}] ns^{1}$$

Alkaline earth metal electronic configuration

$$[\text{Noble gas}] ns^{2}$$

Hydration Energy ($H.E.$) relationship

$$H.E. \text{ is proportional to } \frac{\text{charge}}{\text{size}}$$

Alkali metal density trend anomaly

$Li < Na > K < Rb < Cs$ (where Potassium is less dense than Sodium).

Hardest alkali metal

Lithium ($Li$).

Amphoteric oxide in S-block

Beryllium Oxide ($BeO$).

Superoxide

Compounds represented as $MO_{2}$ (e.g., $KO_{2}$, $RbO_{2}$, $CsO_{2}$) which are paramagnetic; $CsO_{2}$ is yellow-orange.

Lithium reaction with Nitrogen

$6Li + N_{2} \rightarrow 2Li_{3}N$ (Lithium is the only alkali metal to react directly with Nitrogen).

Refractory materials

Materials such as $BeO$ and $MgO$ that can withstand high temperatures.

Beryllium's exclusion from alkaline earth metals

Beryllium is sometimes not counted as an alkaline earth metal because it does not form a basic oxide.

Polyhalide formation

$K$, $Rb$, and $Cs$ form polyhalides, such as $KI + I_{2} \rightarrow KI_{3}$ (Brown).

Alkali metal liquid ammonia solution (Blue)

A solution of alkali metal in liquid ammonia that is blue, paramagnetic, and reducing due to ammoniated electrons ($e^{-}(\text{NH}_{3})_{y}$).

Diagonal relationship

The similarity in properties between elements placed diagonally in the periodic table, such as $Li$ and $Mg$, or $Be$ and $Al$.

Sodium-potassium pump

A discriminatory mechanism operating across cell membranes that consumes more than one-third of the ATP used by a resting animal.

Chlorophyll

The main pigment for light absorption in plants, which contains magnesium ($Mg$).

Quick lime

Calcium Oxide ($CaO$).

Slaked lime

Calcium Hydroxide ($Ca(OH)_{2}$).

Bleaching powder preparation

$$Ca(OH)_{2} + Cl_{2} \rightarrow CaOCl_{2} + CaCl_{2} + H_{2}O$$

Castner-Kellner cell

An electrolytic cell used for the preparation of Caustic Soda ($NaOH$) using a mercury ($Hg$) cathode and graphite anode.

Solvay process

A industrial method to prepare Washing Soda ($Na_{2}CO_{3} \text{·} 10H_{2}O$) using $NH_{3}$, $CO_{2}$, $H_{2}O$, and $NaCl$.

Sorel Cement

A mixture used for dental filling formed from $MgO$ and $MgCl_{2}$.

Plaster of Paris (POP)

$CaSO_{4} \text{·} \frac{1}{2}H_{2}O$ formed by heating Gypsum to $120^{\text{o}}C$.

Dead Burnt Plaster

Anhydrous Calcium Sulfate ($CaSO_{4}$) formed by heating Gypsum above $200^{\text{o}}C$.

Cement composition

A mixture of $CaO$, $SiO_{2}$, $Al_{2}O_{3}$, $MgO$, and $Fe_{2}O_{3}$; gypsum is added to slow down the setting process.