Table of contents | |
What are Metals? | |
What are Non-Metals? | |
What are Metalloids? | |
Typical Elements | |
Diagonal relationship |
Metals are elements that are typically good conductors of heat and electricity. They exhibit a shiny appearance when polished, which is known as metallic luster. Metals are generally malleable, meaning they can be hammered into thin sheets without breaking, and ductile, meaning they can be drawn into wires.
Most metals are solid at room temperature, with mercury being a notable exception as it is liquid at room temperature. Metals also tend to have high densities and are often heavy. Chemically, metals tend to lose electrons during reactions, forming positively charged ions known as cations.
Examples of metals include iron (Fe), copper (Cu), gold (Au), and aluminum (Al).
Non-metals are elements that are typically poor conductors of heat and electricity. They usually lack the shiny appearance of metals and can appear dull or glassy. Unlike metals, non-metals are brittle when solid, meaning they break easily and are neither malleable nor ductile. Non-metals can exist in various states at room temperature: they can be solid (like carbon), liquid (like bromine), or gas (like nitrogen).
Non-metals generally have lower densities compared to metals. In chemical reactions, non-metals tend to gain or share electrons, forming negatively charged ions (anions) or covalent bonds. Examples of non-metals include carbon (C), oxygen (O), sulfur (S), and chlorine (Cl).
Metalloids, also known as semimetals, have properties that are intermediate between those of metals and non-metals. They are semi-conductors, meaning they conduct electricity better than non-metals but not as well as metals.
Metalloids often have a metallic luster, making them appear shiny. However, they are generally brittle like non-metals, meaning they break easily and are not malleable or ductile. All metalloids are solid at room temperature. Their densities and other physical properties fall between those of metals and non-metals. Chemically, metalloids can exhibit mixed behavior, sometimes acting like metals and other times like non-metals. Examples of metalloids include silicon (Si), boron (B), germanium (Ge), and arsenic (As).
Elements in the third period, like Na, Mg, Al, Si, P, S, and Cl, are called typical elements. Each group of elements shares similar properties, mostly resembling the characteristics of the typical element within that group.
Some elements of certain groups of 2nd period resemble much in properties with the elements of third period of next group i.e. elements of second and third period are diagonally related in properties. This phenomenon is known as diagonal relationship.
Diagonal relationship arises because of
(a) Li and Mg both reacts directly with nitrogen to form lithium nitride (Li3N) and magnesium nitride (Mg3N2) whereas other alkali metals of I A group does not form nitride.
(b) Fluoride, carbonate and phosphate of Li and Mg are insoluble in water whereas these compounds of other alkali metals are soluble.
(c) Li and Mg both are hard metals, whereas other metals of I A group are soft.
(d) LiOH and Mg(OH)2 both are weak bases, whereas hydroxides of other elements of IA group are strong base.
(f) Metallic bond in Li and Mg both are strong compare to other alkali metals.
(g) Their melting and boiling points are high.
(h) By thermal disintegration of LiNO3 and Mg (NO3)2 ; Li2O and MgO is obtained respectively.
(I) Thermal stability of Li2CO3 and Mg CO3 is very less compare to other alkali metals and they liberates CO2 gas easily.
(b) They both are comparatively stable in air.
(c) Both are insoluble in NH3, therefore, do not form blue coloured solution.
(d) There is no tendency of making peroxide and superoxide in them.
(e) Reducing power is very less due to low value of standard electrode potential in the form of oxidation potential.
(f) Be and AI both forms halogen bridge halides.
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1. What are the differences between metals, non-metals, and metalloids? |
2. Can you provide examples of typical elements classified as metals, non-metals, and metalloids? |
3. What is the diagonal relationship in the periodic table of elements? |
4. How are the properties of metals, non-metals, and metalloids useful in various industries? |
5. Why is it important to understand the classification of elements into metals, non-metals, and metalloids? |
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