Relation Between Metals and Non Metals, Physical & Chemical Properties
All elements present on the planet have been properly arranged based on their increasing atomic numbers in a periodic table. In total, there are 118 elements known to us, of which 92 are obtained naturally while the rest 26 are artificially synthesized in the laboratory. These elements can be broadly classified based on their physical and chemical properties into three: Metalloids, Metals, and Non-Metals.
The elements that form electropositive ions by donating electrons to form bonds are called metals. Metals are present in the periodic table under the groups: alkali metals, alkaline earth metals, and transition metals. Based on the group in which the metal is present, the element loses either 1, 2, or more electrons to form positive ions.
Physical Properties of Metals:
The atoms of metal are held together with the help of metallic bonds. These metallic bonds have free mobile electrons in them that confer various physical properties to the metal.
- At room temperature, metals are present as solids. Mercury is an exception that exists as a liquid at room temperature. Also, Gallium tends to liquify on a slight elevation in temperature.
- Metals have a rigid crystalline structure. Except for sodium and potassium, they exist as soft metals.
- Metals have lustrous surfaces. The free electrons of the metal absorb and emit rays which give the metal a shiny reflective surface.
- Metals are good conductors of heat and electricity. This is because the non-localized electrons can carry a charge and kinetic energy from one end of the metal to another.
- The property of malleability and ductility is peculiar to metals. As metals can be beaten into sheets, like the aluminium foil and can be drawn into wires like copper wires.
- The metallic bonds present in the metal are extremely strong, and the amount of energy required to break such bonds is relatively high. Hence, metals have high melting and boiling points.
Chemical Properties of Metals:
- The number of electrons present in the outermost valence shell of metal ranges from 1 to 3. These small number of valence electrons are loosely attracted to the nucleus, thus allowing the easy release of electrons from the valence shell.
- Metals react with oxygen to form oxides that are basic in nature. These basic oxides can further be converted to hydroxides on reaction with water.
- The basic metal oxides can also react with acids to undergo a neutralization reaction, forming salt and water.
- Metals and non-metals undergo reactions to form ionic compounds.
Non-metals are those elements that have partially filled electrons in their outermost shell. Because of the presence of a large number of valence electrons, these elements tend to attract electrons from neighbouring atoms and form anions. Thus, non-metals are electronegative elements.
Physical Properties of Non-Metals:
- At room temperature, non-metals can exist as a solid or a gas. However, except for bromine, it is a liquid non-metal at room temperature.
- Non-metals are brittle, hence lack the property of ductility and malleability.
- Non-metals also lack lustre and are bad conductors of electricity. Example: Wood.
- The melting temperatures of non-metals are extremely lower than that of metals.
Chemical Properties of Non-Metals
- There are around seven non-metals that exist as diatomic molecules at normal room temperature. Some of the diatomic gases are hydrogen, oxygen and nitrogen.
- Unlike metals, non-metals react with oxygen to form acid or neutral oxides. These acidic oxides can react with water to form hydroxides.
- These acidic oxides of non-metal can react with bases to form the products of salt and water.
- The atoms of a non-metal are held together by covalent bonds.
Metalloid: The third category of elements is called metalloids. The properties of metalloids are in between the metals and non-metals. These elements tend to display physical properties like that of metals but have chemical properties similar to non-metals.
Example: Silicon, Germanium. A speciality of metalloids is their ability to form semi-conductors. These metalloids are inherently poor conductors of electricity, but their conductivity can be enhanced by doping.
Difference Between Metals and Non-Metals
|Metals are electropositive.
|Non-metals are electronegative.
|Metals tend to exist in a solid state at room temperature. (Except Mercury)
|Non-metals can exist as either solid or gas. (Except Bromine)
|Metals are good conductors of heat and electricity
|Non-metals are bad conductors of electricity (Except graphite) and heat.
|Metals can be beaten to sheets.
|Non-metals are brittle and cannot be moulded.
|Example: Sodium, Magnesium
|Example: Carbon, Oxygen