Chemistry · Ch 2 — p-Block Elements-I
Metallic Nature
Metallic Nature
Metallic (electropositive) character is an element's tendency to lose electrons and form a cation; it tracks directly with ionisation energy -- the lower the ionisation energy, the more readily an element gives up an electron, and hence the more metallic it is. Because ionisation energy generally falls on descending a group, metallic character generally rises down a group (Figure 2.1).
Across the p-block as a whole, elements toward the lower-left are metals, while elements toward the upper-right are non-metals, with metalloids forming a diagonal band in between. Group 13 is metallic throughout except for its very first member, boron, which is a metalloid -- its small atomic radius and correspondingly high effective nuclear charge give it properties intermediate between a metal and a non-metal. Moving to later groups, the non-metallic character of the first few members increases: in group 14, carbon is a non-metal while silicon and germanium are metalloids (tin and lead are metals); in group 15, nitrogen and phosphorus are non-meta …
What this figure shows. A periodic grid of groups 13-18 (rows for each period) in which every element's box is colour-coded by category -- metal, metalloid, non-metal or radioactive -- and each box is printed with the element's first ionisation enthalpy (kJ mol⁻¹) and Pauling electronegativity value beneath its symbol, letting the metallic-character gradient across the p-block be read off directly. …