Physical Properties of Metals and Non-Metals

Introduction and Explanation

A chemical element is a substance that cannot be broken down by chemical means. There are 118 known elements. An element can be classified into:

• Metals
• Non-metals
• Metalloid (possesses the property of both metal and non-metals)

What Are Physical Properties?

All elements have different physical properties depending on their bonding and their electronic structure. These properties very often determine their relationship with temperatures, textures, and other substances when they are dissolved. Some of these physical properties are appearance, melting point, boiling point, density, solubility, and texture. These properties differ from metals to non-metals but are usually quite similar in groups due to elements being grouped based on their similar physical and chemical properties.

For example, all group 1 metals are soft metals and they can float on water as they are less dense than water. A similar pattern can be seen in halogens which belong to group 17. All of the halogens are coloured elements and they all have low melting and boiling points due to their weak intermolecular forces.

What is Metal?

Metals are formed naturally below the surface of the Earth. Most metals are lustrous or shiny. They are made of substances that were never alive, and because of that, they are inorganic. Metals are natural compounds of the earth’s crust, which are generally found in the form of metal ores, associated both with each other and with many other elements. They are also present in the rocks washed by groundwater and surface water.

Physical Properties of Metals:

1. Metals Are Malleable:

They are malleable because they can be beaten into thin sheets. This property is called malleability. In the manufacturing of aircraft, they use aluminum sheets because of their lightweight and strength. Other sheets are used in industries.

2. Metals Are Ductile:

They can be drawn into wires. This property is called ductility. They can be used in cable wires and for soldering purposes. Gold is the most ductile metal.

3. They Are Lustrous in Nature:

They have a shining surface when they are in their pure state. This property is known as metallic luster. Due to this property, they are used in the making of jewelry.

4. They Are Sonorous in Nature:

They produce a pleasant sound on striking and are said to be sonorous. They produce a deep or ringing sound when struck with another hard object. That’s why school bells are made up of metals to produce a ringing sound.

5. They Are Hard in Nature:

The hardness varies from metal to metal.

Exception: Alkali metals (lithium, sodium, potassium) are soft in nature.

6. They Are Fine Conductors of Heat and Electricity:

As they are good conductors of both heat and electricity so they are used to make cooking utensils.

Also, electrical wires are covered with a layer of plastic to make them safe because plastic is an insulator.

Exception: Lead and Mercury conducts heat and electricity poorly.

7. Melting and Boiling Points Are High for them:

They have high melting and boiling points because the number of electrostatic forces to be broken is extremely large as they have giant lattice structures. This means they have similar melting and boiling points to those of ionic compounds to covalent substances.

Exception: Gallium and cesium have low melting points.

8. They Are Generally Solid at Room Temperature:

The metals are solid at room temperature because their melting point can’t be reached at room temperature because they have strong inter molecule forces of attraction which cannot be broken at energy provided at room temperature.

Exception: At room temperature, mercury is found in a liquid state.

What Is a Non-metal?

Non-metals are the elements that form negative ions by accepting or gaining electrons. Generally, they have 4, 5, 6, or 7 electrons in their outermost shell. They lack all metallic attributes. They do not conduct heat and electricity so they are insulators. They are mostly gases and sometimes liquid.

Physical Properties of Non-metals:

1. Non-metals Are Non-malleable:

Non-metals cannot be beaten into thin sheets. They can’t be drawn into sheets as they are brittle and break on applying pressure.

2. Non-metals Are Non-ductile:

Ductility is the property of the material to be stretched into wires but non-metals are not ductile except for carbon, as carbon fibres find uses in a wide variety of industries including sports and music equipment.

3. Non-metals Are Non-lustrous in Nature:

Non-metals vary greatly in appearance. They do not have lustre. As it does not have any free electrons. Light falling on non-metals does not reflect and hence non-metals are not shiny.

Exception: Iodine has a shining surface.

4. They Are Non-sonorous in Nature:

Non-metals do not produce a ringing sound when beaten. Thus, non-metals are non-sonorous. They produce a dull sound when they are hit.

5. They Are Soft in Nature:

They are brittle or dull and soft. When hit down by a hammer they can be broken down into a powdery substance. A few examples are coal and sulphur. Exception: Diamond is a non-metal but it is one of the hardest elements in nature.

6. They Conduct Heat and Electricity Poorly:

They do not have an ample amount of free electrons to pass electricity efficiently. The electrons of non-metal are held tightly, they are not allowed to move freely.

Exception: Graphite is a non-metal but it is a good conductor of electricity.

7. Melting and Boiling Points Are Low for Non-metals.

These non-metals have sub-zero melting point temperatures because they have a high affinity for electrons and effectively pry them from the other atom, so the bond breaks easily.

Exception: Diamond and graphite have high melting and boiling points.

8. Non-metals Exist as Solids, Liquids, and Gases at Room Temperature:

• Solid – Sulphur
• Liquid – Bromine
• Gas- Hydrogen, nitrogen

Difference Between Metals and Non-metals on the Basis of Physical Properties.

Summary

• A metal is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well.
• Metals are malleable, ductile, sonorous, lustre, and good conductors of electricity and heat.
• A nonmetal is simply an element that does not display the properties of a metal.
• Non-metals are non-malleable, non-ductile, non-sonorous, non-lustre, and bad conductors of electricity and heat.