What are the properties of metal?
Properties of elements distinguish them into metals and nonmetals. Such as metals are those elements that are malleable, ductile, sonorous, and good conductors of heat and electricity. While nonmetals are those elements that are not malleable, ductile, sonorous, and are poor conductors of heat and electricity.
Metals and non-metals have different properties and different reactions. These differences in reactivity depend on where an element is placed in the periodic table.
Properties of Metals and Non-Metals- What’s the Difference?
|State at room temperature||Solid (except mercury, which is a liquid)||About half are solids, about half are gases, and one (bromine) is a liquid|
|Density||High (they feel heavy for their size)||Low (they feel light for their size)|
|Malleable or brittle||Malleable (they bend without breaking)||Brittle (they break or shatter when hammered)|
|Conduction of heat||Good||Poor (they are insulators)|
|Conduction of electricity||Good||Poor (they are insulators, apart from graphite)|
|Magnetic material||Only iron, cobalt, and nickel||None|
|Sound when hit||They make a ringing sound (they are sonorous)||They make a dull sound|
|Type of oxide||Basic or alkaline||Acidic|
In this article, we will discuss the properties of metals and nonmetals and the difference between the two on the basis of their properties (with exceptions) in detail.
Properties of Metal
With the exception of hydrogen, all elements that form positive ions by losing electrons during chemical reactions are called metals. Thus, metals are electropositive elements with relatively low ionization energies. They are characterized by bright luster, hardness, ability to resonate sound, and are excellent conductors of heat and electricity. Metals are solids under normal conditions except for Mercury.
Physical Properties of Metals
Metals are lustrous, malleable, ductile, good conductors of heat and electricity. Other properties include:
- State: Metals are solids at room temperature with the exception of mercury, which is liquid at room temperature (Gallium is liquid on hot days).
- Luster: Metals have the quality of reflecting light from their surface and can be polished e.g., gold, silver and copper.
- Malleability: Metals have the ability to withstand hammering and can be made into thin sheets known as foils. For example, a sugar cube sized chunk of gold can be pounded into a thin sheet that will cover a football field.
- Ductility: Metals can be drawn into wires. For example, 100 g of silver can be drawn into a thin wire about 200 meters long. The structure of metals consists of layers of metal ions. These layers can slide over each other when a force is applied. This means that the layers of the metal can be hammered flat, and they can also slide over each other to make thin wires. Metallic bonding allows the metal to change shape without shattering.
- Hardness: All metals are hard except sodium and potassium, which are soft and can be cut with a knife.
- Valency: Metals typically have 1 to 3 electrons in the outermost shell of their atoms.
- Conduction: Metals are good conductors because they have free electrons. When a voltage is applied to a metal, the delocalized electrons travel through the lattice structure. The movement of these charged particles forms an electric current. Notice that the metal ions in the metallic lattice are held in fixed positions and are not able to move. Silver and copper are the two best conductors of heat and electricity. Lead is the poorest conductor of heat. Bismuth, mercury and iron are also poor conductors.
- Density: Metals have high density and are very heavy. Iridium and osmium have the highest densities whereas lithium has the lowest density.
- Melting and Boiling Points: Metals have high melting and boiling points. Tungsten has the highest melting and boiling points whereas mercury has the lowest. Sodium and potassium also have low melting points.
Chemical Properties of Metals
Metals are electropositive elements that generally form basic or amphoteric oxides with oxygen. Other chemical properties include:
- Electropositive Character: Metals tend to have low ionization energies, and typically lose electrons (i.e. are oxidized) when they undergo chemical reactions They normally do not accept electrons. For example:
- Alkali metals are always 1+ (lose the electron in s subshell)
- Alkaline earth metals are always 2+ (lose both electrons in s subshell)
- Transition metal ions do not follow an obvious pattern, 2+ is common (lose both electrons in s subshell), and 1+ and 3+ are also observed
Compounds of metals with non-metals tend to be ionic in nature. Most metal oxides are basic oxides and dissolve in water to form metal hydroxides:
Metal oxides exhibit their basic chemical nature by reacting with acids to form metal salts and water:
Properties of Nonmetals
Elements that tend to gain electrons to form anions during chemical reactions are called non-metals. These are electronegative elements with high ionization energies. They are non-lustrous, brittle, and poor conductors of heat and electricity (except graphite). Non-metals can be gases, liquids, or solids.
Physical Properties of Nonmetals
- Physical State: Most of the non-metals exist in two of the three states of matter at room temperature: gases (oxygen) and solids (carbon). Only bromine exists as a liquid at room temperature.
- Non-Malleable and Ductile: Non-metals are very brittle, and cannot be rolled into wires or pounded into sheets.
- Conduction: They are poor conductors of heat and electricity.
- Luster: These have no metallic luster and do not reflect light.
- Melting and Boiling Points: When a metal melts or boils, this is a change of physical state. Energy is transferred to a substance to melt or boil it. This energy is needed to overcome the forces of attraction between the metal ions and the delocalized electrons in the metal. The more energy needed, the higher the melting point or boiling point. As metals are giant lattice structures, the number of electrostatic forces to be broken is extremely large, and so metals have high melting and boiling points. This means that the melting point and boiling point of metals are more similar to those for ionic compounds than for covalent substances.
- Seven non-metals exist under standard conditions as diatomic molecules: H2(g)H2(g), N2(g)N2(g), O2(g)O2(g), F2(g)F2(g), Cl2(g)Cl2(g), Br2(l)Br2(l), I2(s)I2(s).
Chemical Properties of Nonmetals
Non-metals have a tendency to gain or share electrons with other atoms. They are electronegative in character. Nonmetals, when reacting with metals, tend to gain electrons (typically attaining noble gas electron configuration) and become anions:
Compounds composed entirely of nonmetals are covalent substances. They generally form acidic or neutral oxides with oxygen that dissolve in water to form acids:
CO2(g)+H2O(l)→H2CO3(aq)carbonic acidCO2(g)+H2O(l)→H2CO3(aq)carbonic acid
As you may know, carbonated water is slightly acidic (carbonic acid).
Nonmetal oxides can combine with bases to form salts.
Properties of Metalloids
Metalloids have properties intermediate between metals and nonmetals. Metalloids are useful in the semiconductor industry. Metalloids are all solid at room temperature. They can form alloys with other metals.
Some metalloids, such as silicon and germanium, can act as electrical conductors under the right conditions, thus they are called semiconductors. Silicon for example appears lustrous but is not malleable nor ductile (it is brittle – a characteristic of some nonmetals).
It is a much poorer conductor of heat and electricity than metals. The physical properties of metalloids tend to be metallic, but their chemical properties tend to be non-metallic. The oxidation number of an element in this group can range from +5 to -2, depending on the group in which it is located.
Common Properties of Metalloids
In general, metalloids share the following common properties:
- The electronegativities of metalloids are between those of nonmetals and metals.
- Ionization energies of metalloids are also between those of nonmetals and metals.
- Semimetals/metalloids have some characteristics of nonmetals and some characteristics of metals.
- The reactivity of metalloids depends on the properties of the elements they are interacting with.
- Metalloids tend to be good semiconductors.
- Metalloids may have a metallic luster, but they also have our tropes which can have a nonmetallic appearance.
- Metalloids are usually brittle, and they are also typically solid, only becoming non-solid under uncommon conditions.
- Metalloids typically behave as nonmetals in chemical reactions, and they can create alloys with metals.
Chemical properties of Metalloids
Chemical properties are those which defined how a substance interacts/reacts with other substances or changes one substance to another substance. Chemical reactions are the only time that the chemical properties of an element can be quantified. Chemical reactions include things like rushing, burning, tarnishing, exploding, etc. The chemical properties of metalloids are as follows:
- Metalloids easily form gasses when they oxidize.
- Metalloids can be combined with metals to create alloys.
- Metalloids have different metallic and non-metallic allotropes.
- When metalloids melt some of them will contract.
- Metalloids can react with halogens to form compounds.
Trends in Metallic and Nonmetallic Character
Metallic character is strongest for the elements in the leftmost part of the periodic table and tends to decrease as we move to the right in any period (nonmetallic character increases with increasing electronegativity and ionization energy values).
Within any group of elements (columns), the metallic character increases from top to bottom (the electronegativity and ionization energy values generally decrease as we move down a group). This general trend is not necessarily observed with the transition metals.