In this tutorial, you will learn about the properties of metals, nonmetals, and metalloids (semimetals) as well as examples of metal elements, and nonmetal elements. Show
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VocabularyDuctility – the ability to be drawn into wires Malleability – the ability to be hammered into thin sheets Luster – the quality of reflecting light from the surface and can be polished Introduction to Metals, Metalloids, and NonmetalsAn element is a substance that cannot be broken down into any other substance. In other words, an element is the simplest form of matter. Elements are further classified into metals, non-metals, and metalloids (semimetals). Nonmetals are generally on the upper right side of the periodic table, metals cover most of the remaining area with metalloids in-between them. Properties of MetalsMetals are elements that form positive ions by losing electrons during chemical reactions, except hydrogen. Thus, they are electropositive elements with low ionization energies. Most metals share the properties of being shiny, very dense, and having high melting points. Furthermore, they are ductile, malleable, and lustrous. Metals are also good conductors of heat and electricity. All metals are solids at room temperature, except mercury which is a liquid. Metals generally form ionic bonds with nonmetals, but there are exceptions. Most metals form at least one basic oxide, although some are amphoteric. Metals exhibit a wide range of reactivity. Special groups of metals include the noble metals Ru, Rh, Pd, Pt, Au, Os, Ir, Ag and the refractory metals Nb, Mo, Ta, W and Re. Metal Properties:
Examples of Metals
Properties of NonmetalsNonmetals are elements that form negative ions by gaining electrons during chemical reactions. Thus, they are electronegative elements with high ionization energies. In general, non-metals are brittle, dull, and poor conductors of heat and electricity. They tend to have lower melting points than metals. Most of non-metals exist in two of the three states of matter at room temperature: gases and solids, except bromine, which exists as a liquid. Examples of Nonmetal Elements
Properties of Metalloids, aka SemimetalsSemimetals, also known as metalloids, have properties of both metals and non-metals. All metalloids are solids. Metalloids can be shiny or dull, but usually have a metallic luster. Some forms of selenium have an amazing, almost space-like sheen. They are brittle, and are typically semi-conductors. Semi-conductors are capable of conducting electricity better than insulator, but not as well as conductors. Metalloids generally have chemical properties similar to non-metals. Most form several different anions with oxygen that make a variety of salts with metals, although the aqueous chemistry of germanium is more limited. They act as metals when reacting with halogens, and as non-metals when reacting with alkali metals. Germanium is heavily used in the semiconductor industry. Some semimetals like selenium and arsenic can be toxic. A selenium speciation machine can measure the amount of selenium present. Five Main Properties of Metalloids
Examples of Metalloids
An element is the simplest form of matter that cannot be split into simpler substances or built from simpler substances by any ordinary chemical or physical method. There are 118 elements known to us, out of which 92 are naturally occurring, while the rest have been prepared artificially. Elements are further classified into metals, non-metals, and metalloids based on their properties, which are correlated with their placement in the periodic table.
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.
Metals are lustrous, malleable, ductile, good conductors of heat and electricity. Other properties include:
Metals are electropositive elements that generally form basic or amphoteric oxides with oxygen. Other chemical properties include:
\[\ce{Na^0 \rightarrow Na^+ + e^{-}} \label{1.1} \] \[\ce{Mg^0 \rightarrow Mg^{2+} + 2e^{-}} \label{1.2} \] \[\ce{Al^0 \rightarrow Al^{3+} + 3e^{-}} \label{1.3} \] 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: \[\ce{Na2O(s) + H2O(l) \rightarrow 2NaOH(aq)}\label{1.4} \] \[\ce{CaO(s) + H2O(l) \rightarrow Ca(OH)2(aq)} \label{1.5} \] Metal oxides exhibit their basic chemical nature by reacting with acids to form metal salts and water: \[\ce{MgO(s) + HCl(aq) \rightarrow MgCl2(aq) + H2O(l)} \label{1.6} \] \[\ce{NiO(s) + H2SO4(aq) \rightarrow NiSO4(aq) + H2O(l)} \label{1.7} \]
What is the chemical formula for aluminum oxide?
Al has a 3+ charge, the oxide ion is \(O^{2-}\), thus \(Al_2O_3\).
Would you expect it to be solid, liquid or gas at room temperature?
Oxides of metals are characteristically solid at room temperature
Write the balanced chemical equation for the reaction of aluminum oxide with nitric acid: Solution
\[\ce{Al2O3(s) + 6HNO3(aq) \rightarrow 2Al(NO3)3(aq) + 3H2O(l)} \nonumber \]
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
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: \[\ce{3Br2(l) + 2Al(s) \rightarrow 2AlBr3(s)} \nonumber \] Compounds composed entirely of nonmetals are covalent substances. They generally form acidic or neutral oxides with oxygen that that dissolve in water to form acids: \[\ce{CO2(g) + H2O(l)} \rightarrow \underset{\text{carbonic acid}}{\ce{H2CO3(aq)}} \nonumber \] As you may know, carbonated water is slightly acidic (carbonic acid). Nonmetal oxides can combine with bases to form salts. \[\ce{CO2(g) + 2NaOH(aq) \rightarrow Na2CO3(aq) + H2O(l)} \nonumber \]
Metalloids have properties intermediate between the 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 the 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.
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. Non metallic character increases bottom to top and left to right with the most nonmetal element in the top right corner. metallic character shows the opposite trend with the most metallic element being in the bottom left. |