If an element breaks when it is struck with a hammer, could it be a metal? Explain.

Metals are prized for their malleability, a property that allows them to be shaped or deformed without cracking or breaking. This characteristic is why we can hammer metals into thin sheets, known as foils, or mold them into various forms. For instance, gold, one of the most malleable metals, can be hammered into sheets so thin that they appear almost transparent.

Understanding malleability is crucial for industries such as automotive or aerospace, which require materials that can withstand deformation during manufacturing without failing. In terms of our exercise, while the element broke when struck, this does not immediately dismiss it as a metal. Some metals, like cast iron, are less malleable and can be brittle, leading them to break under certain conditions.

Ductility is another cherished metallic property, closely related to malleability. It describes a metal's ability to be drawn out into a thin wire without breaking. Copper and aluminum are prime examples, widely used in electrical wiring because of their excellent ductility and electrical conductivity.

This property is harnessed in countless applications, from the delicate jewelry that adorns people globally to the vast networks of electrical cables that power our cities. In educational settings, illustrating the process of drawing a wire from a metal ingot can be a practical demonstration of ductility. However, not all metals showcase this property to the same extent, and some may indeed break instead of stretching into a wire.

The physical state of metals under standard conditions—room temperature (around 20°C) and atmospheric pressure—typically is a solid. This solid state contributes significantly to the durability and structural integrity of metals. You'll find that vast bridges, towering skyscrapers, and even the humble paperclip all rely on the solidity of metals like steel, iron, and nickel.

There are, of course, exceptions to this rule. Mercury is a well-known metal that is liquid at room temperature, demonstrating that the physical state can vary among metals. Thus, when considering the exercise question, if an element breaks when struck, it could still potentially be a metal with a lower melting point or one that displays brittleness at room temperature.

Hardness is indicative of how resistant a material is to various kinds of permanent shape change when a compressive force is applied. Metals tend to rank highly on the scale of hardness, which is why they're the go-to materials for applications that require durability and resistance to wear and tear. Tools, machinery, and engines are some everyday uses of hard metals such as tungsten and steel.

However, the hardness of metals is not uniform across the board. Some metals may actually be quite soft, like lead, or can be brittle under certain conditions or at specific purities, which could lead to them breaking when struck by a hammer. It's pivotal for students to recognize that while hardness is a characteristic of metals, variances exist within the metal category itself.