Untitled Quiz

Materials made up of the same kind of particles are known as pure substances
A given element or compound is a pure substance because it is made up of atoms or molecules of the same kind
Different elements or compounds differ in their physical and chemical properties since they are made up of different kinds of atoms or molecules

There are approximately 118 elements known today
Classifying all the properties of individual elements separately is difficult
Elements with similar properties are grouped together to study their general characteristics
Elements are broadly classified into metals and nonmetals, based on their physical and chemical properties

Metals are abundant in the Earth's crust, with aluminum being the most abundant
Metals like sodium, potassium, aluminum, and magnesium are often found in their compound forms (oxides, sulphides, carbonates)
Many non-metals are found in their free state in the atmosphere (oxygen, nitrogen)
Some non-metals can exist either in their pure form or as compounds (sulphur)
Some non-metals exist in different forms in their native state (carbon - diamond, graphite, fullerene)

A mineral is a naturally occurring inorganic substance found underground
An ore is a mineral from which one or more metals can be extracted profitably (ex: bauxite for aluminum, hematite for iron)
Metallurgy is the process of extracting a metal in pure form from its ore, this process generally involves concentration and reduction of the ore, and refining of the metal

Physical State: Most metals are solid at room temperature, with mercury being the exception (liquid)
Melting and Boiling Points: Metals typically have high melting and boiling points (exceptions exist); non-metals tend to have lower melting and boiling points (exceptions exist)
Density: Most metals have relatively high densities, some exceptions exist in metals such as sodium and potassium
Hardness: Most metals are hard, exceptions include sodium and potassium; non-metals are generally brittle and break easily
Lustre: Metals shine (metallic luster); non-metals often have a dull appearance, iodine being an exception
The properties of metals and non-metals differ

Malleability: Metals can be hammered into thin sheets without breaking; non-metals are brittle
Ductility: Metals can be drawn into thin wires; non-metals are often not ductile
Tensile Strength: Metals are generally strong; non-metals (with exceptions like carbon fiber) generally aren't as strong
Conductivity: Metals are good conductors of heat and electricity; non-metals, with exceptions like graphite, are generally poor conductors

Reaction with Oxygen: Metals typically react with oxygen to form metallic oxides, which are basic in nature. Non-metals react with oxygen to form non-metallic oxides that are, in most cases, acidic.
Reaction with Water: Some reactive metals (e.g., sodium, potassium, magnesium) react vigorously with water, while others (e.g., copper, silver, gold) do not. Non-metals generally do not react with water.
Reaction with Acids: Most metals react with dilute acids to liberate hydrogen gas and form metal salts (e.g., zinc with hydrochloric acid); some metals do not react with certain acids, or won't react with acids in their cold state
Reaction with Alkalis: Some metals (e.g., aluminum, zinc) react with alkalis to form their salts and liberate hydrogen gas. Most metals do not react with alkalis

Metals vary in their reactivity; reactivity series of metals can be used to identify the relative reactivity of different metals;
More reactive metals are placed at the top of the series; less reactive metals are closer to the bottom

More reactive metals can displace less reactive metals from their compounds or solutions.
This process is called displacement reaction

Noble metals (e.g., platinum, gold) are unreactive and do not react with most substances;
They retain their lustre even when exposed to the environment
They are malleable and ductile and are often used in jewelry

Metals are used in many applications including cooking, electrical wiring; alloys, which are homogenous mixtures of two or more metals, are also employed in various applications
Non-metals are essential to many industries and processes include industrial manufacturing of materials such as fertilizers, and for agricultural activities.