Lithium diagonal relationship with

The properties of the head element of a main group in the periodic table resemble those of the second element in the next group. Discuss this diagonal relationship with particular reference to (a) lithium and magnesium, (b) beryllium and aluminium. 

Lithium (Li), an alkali metal, has properties similar to and has a diagonal relationship with —... 

I- ions. Lithium, the least reactive alkali metal, has a diagonal relationship with magnesium, a group 2A metal. Sodium and potassium are the most abundant alkali metals. The most common sodium... 

The small size of lithium frequently confers special properties on its compounds and for this reason the element is sometimes termed anomalous . For example, it is miscible with Na only above 380° and is immiscible with molten K, Rb and Cs, whereas all other pairs of alkali metals are miscible with each other in all proportions. (The ternary alloy containing 12% Na, 47% K and 41% Cs has the lowest known mp, —78°C, of any metallic system.) Li shows many similarities to Mg. This so-called diagonal relationship stems from the similarity in ionic size of the two elements / (Li ) 76pm, / (Mg ) 72pm, compared with / (Na ) 102pm. Thus, as first noted by Arfvedson in establishing lithium as a new element, LiOH and LiiCOs are much less soluble than the corresponding... 

The diagonal band of metalloids dividing the metals from the non-metals is one example of a diagonal relationship (Section B). So is the chemical similarity of lithium and magnesium and of beryllium and aluminum. For example, both lithium and magnesium react directly with nitrogen to form nitrides. Like aluminum, beryllium reacts with both acids and bases. We shall see many examples of this diagonal similarity when we look at the elements in detail (in Chapters 14 and 15). 

Lithium and magnesium exhibit a diagonal relationship in some chemical properties. How does lithium resemble magnesium in its reaction with oxygen and nitrogen Consult a handbook of chemistry and compare the solubilities of carbonates, fluorides, and phosphates of these metals. 

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