What is the acid base behavior of element oxides? Information and examples about acid base behavior of some common oxides
Acid Base Behavior Of Element Oxides; Metals are also distinguished from nonmetals by the acid-base behavior of their oxides in water:
• Most main-group metals transfer electrons to oxygen, so their oxides are ionic. In water, these oxides act as bases, producing OH– ions and reacting with acids. Calcium oxide is an example.
• Nonmetals share electrons with oxygen, so non-metal oxides are covalent. In water, they act as acids, producing H+ ions and reacting with bases. Tetraphosphorus decaoxide is an example.
Figure on the right classifies the acid-base behavior of some common oxides, focusing once again on the elements in Group 5A, dinitrogen pentaoxide, N2O5, forms nitric acid:
Tetraphosphorus decaoxide, P4O10, forms the weaker acid H3PO4:
The oxide of the metalloid arsenic is weakly acidic, whereas that of the metalloid antimony is weakly basic. Bismuth, the most metallic of the group, forms a basic oxide that is insoluble in water but that forms a salt and water with acid:
Note that as the elements become less metallic across a period, their oxides become more acidic. In Period 3, sodium and magnesium form the strongly basic oxides Na2O and MgO.
Some metals and many metalloids form oxides that are amphoteric: they can act as acids or as bases in water. Metallic aluminum forms amphoteric aluminum oxide (Al2O3), which reacts with acid or with base:
Silicon dioxide is weakly acidic, forming a salt and water with base:
The common oxides of phosphorus, sulfur, and chlorine form acids of increasing strength: H3PO4, H2SO4, and HClO4.
So the metallic properties decreases from left to right across a period, and increases from top to bottom within a group Most of the periodic properties of elements are summarized in below.
Comparison of Periodic Properties in Periodic Table
|1||Within period from left to right||1||Down a group from top to bottom|
|1.||Atomic number increases.||1.||Atomic number increases.|
|2.||Mass number increases.||2.||Mass number increases.|
|3.||Atomic volume decreases.||3.||Atomic volume increases.|
|4.||lonazation energy increases.||4.||lonazation energy decreases.|
|5.||Electron affinity increases.||5.||Electron affinity decreases.|
|6.||Electron losing tendency decreases.||6.||Electron losing tendency increases.|
|7.||Metallic character decreases.||7.||Metallic character increases.|
|8.||Nonmetallic character increases.||8.||Nonmetallic character decreases.|
|9.||Acidic character of oxides increases.||9.||Acidic character of oxides decreases.|
|10.||Number of valence electrons increases.||10.||Number of valence electrons does not change.|