Chemistry

Chemistry

Problem

A materials scientist is selecting elements to form oxide coatings with specific acid–base character. The table below gives first-ionization energy (IE1_1) and electronegativity (EN) data for four candidate elements.
ElementIE1_1 / kJ mol−1\text{kJ\,mol}^{-1}EN (Pauling)
W4960.93
X7381.31
Y14512.96
Z10002.16
(a) Using the data provided, order the four elements from most metallic to least metallic in their overall chemical behavior. Justify your ranking. (b) Predict whether the oxide of each element will be predominantly basic, amphoteric, or acidic when reacted with water. Briefly explain how the data support each prediction. (c) Element Z is heated in oxygen to form its oxide. Propose a balanced chemical equation showing the reaction of this oxide with water. (d) Suppose the scientist needs an oxide that will react with aqueous hydrochloric acid but not with aqueous sodium hydroxide. Which element’s oxide best fits this requirement? Justify your choice by referring explicitly to parts (a) and (b). a. Part (a) b. Part (b) c. Part (c) d. Part (d)
Intuitive explanation

The key to this problem is recognizing that metallic character and oxide acidity are opposite ends of the same spectrum, controlled by ionization energy and electronegativity. Low IE₁ and low EN mean the element holds onto electrons weakly, forming basic oxides; high IE₁ and high EN mean the element pulls electrons strongly, forming acidic oxides. Use these two properties together to rank metallic behavior and predict oxide character.

Intuitive explanation

The key to this problem is recognizing that metallic character and oxide acidity are opposite ends of the same spectrum, controlled by ionization energy and electronegativity. Low IE₁ and low EN mean the element holds onto electrons weakly, forming basic oxides; high IE₁ and high EN mean the element pulls electrons strongly, forming acidic oxides. Use these two properties together to rank metallic behavior and predict oxide character.

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