Metals and Non-metals — Scientific Principles

Scientific Principles

Four tests, with qualifications

Physical behaviour: distinguish malleability, ductility and conductivity. Malleability concerns sheets; ductility concerns wires. Mercury, graphite and iodine prevent several tempting universal statements about state, conductivity and lustre.

Oxides: many metal oxides are basic and many non-metal oxides are acidic. Aluminium oxide and zinc oxide are amphoteric. A protective oxide layer can change observed corrosion behaviour without making the underlying metal universally unreactive.

Relative reactivity: use the series to predict an appropriate displacement. Iron displaces copper from copper sulphate in the familiar aqueous example; reversing the metals does not reverse the reaction under the same model. Read the specified substances and conditions.

Ionic compounds: electron transfer can form oppositely charged ions. Conductivity requires mobility: a solid ionic lattice differs from a molten compound or suitable solution. The compound's properties are not simply those of the separate elements retained side by side.

Connect chemistry to applications

Extraction depends on reactivity and compound stability. An ore is an economically usable mineral source under the relevant conditions, not every mineral containing the element. Highly reactive metals require different reduction routes from less reactive ones.

Corrosion prevention can use a barrier, a protective metal coating or a change in material through alloying. Explain which mechanism is involved rather than list methods as synonyms.

Final memory check

For each general property, retain an exception. For each reaction, retain its direction and conditions. For each industrial application, name the relevant property. A balanced equation records a chemical relationship; it is not an invitation to conduct an unsupervised experiment.