Question Detail

The diagram on page 19 shows 'Decreasing Basicity' from CO₂ to PbO₂, but this refers to the acidic nature, meaning basicity increases. As elements become more metallic down the group, their oxides tend to become more basic. The text explicitly mentions 'Decreasing Basicity' as a property of the dioxides from top to bottom, which implies that basicity is increasing when moving from a non-metal oxide (acidic) to a metal oxide (basic). However, the arrow points down with 'Decreasing Basicity' written, which is ambiguous. Let's re-evaluate. The diagram has an arrow pointing down from CO2 to PbO2 with 'Decreasing Basicity' on the side. This suggests that CO2 is the most basic, and PbO2 is the least basic, which contradicts general chemical trends (metal oxides are more basic). Let's refer to the monoxides for clarity. Page 18: 'The monoxides are more basic than the dioxides.' and 'Stability of the monoxides increases down the group.' This doesn't directly answer for dioxides basicity trend. However, standard chemical trends dictate that as metallic character increases down a group, the basicity of oxides increases. Given CO2 is acidic, SiO2 is acidic, GeO2 is amphoteric, SnO2 is amphoteric, and PbO2 is amphoteric/slightly basic, the basicity should increase. The diagram's label 'Decreasing Basicity' might be a typo or refer to something else. Assuming standard chemical principles and the trend from acidic non-metal oxides to amphoteric/basic metal oxides, basicity should increase down the group. Let's stick with the general chemical principle which is consistent with the shift from non-metal to metal properties.