Exceptions in Physical Properties of Metals and Non-Metals

Our surrounding is all build-up by various elements and compounds. The composition of elements makes various substances. Now, when we see these building blocks that are elements are further categorized into the groups of metals and non-metals. These elements are differentiated on the basis of their physical and chemical properties. For example, Aluminium is metal because it is shiny, malleable, ductile, etc. Whereas, wood is kept in the group of non-metals as it does not shows any such properties.

Metals are the elements of the periodic table which bear certain physical and chemical properties like are shiny, malleable, conduct electricity, react with acids, etc. Metals are found under the earth's surface in the form of ores and are inorganic. Some metal particles are also present in the atmosphere in form of dust. Mostly, metals are used in the manufacturing of steel, utensils, automobiles, etc. 

Non-Metals are the elements of the periodic table that lack the properties of metals. Non-metals exist in all three states solid, liquid as well as gas. The non-metals present in solid-state are brittle in nature. Hence, they do not bear the properties of malleability and ductility. Non-metals are exclusively used in our daily life activities, used for fuels, treatment, explosions, fertilizers, etc.

Physical Properties of Metals

1. State: Metals exist in a solid-state at room temperature and are hard in nature. While mercury is the only metal that exists in a liquid state at room temperature.
2. Lustrous: Metals are lustrous in nature which means they have a shiny surface. Metals having metallic lustre are used for making jewellery and utensils.
3. High Density: Density of substance means the mass of a substance per unit volume (m/v) and metals have high density.
4. Melting and boiling point: All metals have different melting and boiling points. But generally, all the metals have high melting and boiling points.
5. Malleable: The metals are malleable it means they can be beaten into thin sheets.
6. Ductile: Metals are ductile which means they can be stretched into thin wires,
7. Sonorous: Metals have the property of producing sound. When metals are struck over a hard surface they produce sound due to vibration.
8. Good conductor: Metals are good conductors of heat and electricity. Copper and silver are the best conductors known. Whereas, mercury and lead are poor conductors.

Exceptions in Physical Properties of Metals

• Metals are generally hard in nature and exist in solid-state. But metals like sodium and potassium are soft metals that can easily be cut down. Mercury is also an exception as it exists in a liquid state at room temperature.
• Metals have high density. But Lithium is an alkali metal with a low density of 0.53.
• Metals like gold, silver, platinum and copper do not release hydrogen gas when reacted with acids.
• All metals are sonorous in nature except mercury. This means it does not produce sound when struck on a hard surface.
• All metals are malleable except mercury.
• Metals are solid substances that are insoluble in water but sodium and potassium are the metals that react violently with water to form soluble hydroxides.

Physical properties of Non-metals

1. State: The majority of non-metals are found in gaseous states. While some are also present in a solid or liquid state.
2. Non-lustrous: Generally non-metals do not exhibit any shine or are non-lustorous.
3. Melting and boiling point: Non-metals have low melting and boiling point.
4. Density: Mostly non-metals have lower density.
5. Brittle: Non-metals are brittle in nature which means they can be broken down into pieces. They do not have the property of malleability or ductility.
6. Poor conductor: Non-metals are poor conductors of heat and electricity. It means they do not allow heat or electricity to pass through them.

Exceptions in Physical Properties of Non-Metals

• Unlike other non-metals, graphite and iodine have metallic lustre or shine.
• Carbon although being non-metal has a high melting point.
• Bromine is found in a liquid state at room temperature just as mercury.
• Iodine is a non-metal with a density of 4.9.
• Diamond is the known hardest material although it is a non-metal.

Sample Questions

Question 1: Which element has higher electronegativity metals or non-metals?

Answer:

Electronegativity is the ability of an atom to attract electrons and form chemical bond. As non metals contains 4-8 electrons on their outer valence shell they are more electronegative in nature.

Question 2: Which metal exists in a liquid state at room temperature?

Answer:

Mercury (Hg) is a metal that exists in liquid state at room temperature.

Question 3: What happens when metals are reacted with oxygen?

Answer:

When metals are reacted with oxygen they produce metal oxide or basic oxide.

Metal + Oxygen ⇢ Metal Oxide (Basic oxide)

Question 4: Why gold, silver and platinum are preferred for jewellery?

Answer:

Gold, silver and platinum because they are lustrous or have metallic shine.

Question 5: Is diamond is the hardest but still a non-metal?

Answer:

Diamond is the hardest material because it does not acquires the of metal like malleability, ductility, good conductor,etc.

Question 6: School bells are made up of metals, why?

Answer:

School bells are made up of metals because metals are sonorous in nature that means they produce sound when striked on a hard surface.