You have too often come across this question: Why are some metals more metallic? However, you possibly have always avoided this question. Haven’t you? Well, no more! We will give you all the answers in this chapter. We will cover the periodic trends of the metallic and non-metallic character of elements in this chapter.
Metallic and Non-Metallic Character
We know that elements can either be metals or non-metals. But did you ever wonder if one metal is more metallic than the other? Yes. Steel, which is an alloy of iron, is more metallic than iron. Why is that? This is because of the metallic and non-metallic character of the elements. Let’s understand the metallic and non-metallic character of metals individually.
Browse more Topics under Classification Of Elements And Periodicity In Properties
- Atomic Radius
- Electronegativity and Oxidation State
- Electron Gain Enthalpy
- Historical Development of the Periodic Table
- Ionization Enthalpy and Valency
- Modern Periodic Table
- Periodic Properties of Elements
Metallic Character of a Metal
Metallic character refers to the level of reactivity of a metal. Metals tend to lose electrons in chemical reactions, as indicated by their low ionization energies. Within a compound, metal atoms have a relatively low attraction for electrons. This is indicated by their low electronegativities.
By following the trend summary in the figure below, you can see that the most reactive metals would reside in the lower left portion of the periodic table. The most reactive metal is caesium, which is not found in nature as a free element. It reacts explosively with water and ignites spontaneously in air.
Francium is below caesium in the alkali metal group. However, it is so rare that most of its properties have never been observed.
Non-metallic Character of a Metal
Nonmetals tend to gain electrons in chemical reactions and have a high attraction for electrons within a compound. The most reactive nonmetals reside in the upper right portion of the periodic table. The noble gases are a special group because of their lack of reactivity. However, the element fluorine is the most reactive nonmetal. It is not found in nature as a free element.
Fluorine gas reacts explosively with many other elements and compounds and is considered to be one of the most dangerous known substances.
Note that there is no clear division between metallic and non-metallic character. As we move across the periodic table, there is an increasing tendency to accept electrons (non-metallic) and a decrease in the possibility that an atom would give up one or more electrons(metallic).
- Reactivity of metals is based on processes such as the formation of halide compounds with halogens. We can also determine it on the basis of how easily a metal displaces hydrogen from dilute acids.
- The metallic character increases as you go down a group. Since the ionization energy decreases going down a group (or increases going up a group), the increased ability for metals lower in a group to lose electrons makes them more reactive.
- In addition, the atomic radius increases going down a group, placing the outer electrons further away from the nucleus and making that electron less attracted by the nucleus. Thus, metals become more reactive as we go down the group.
Learn more about the Historical Development of Periodic Table here.
A Solved Example for You
Q: Note down the non-metallic character trends in the periodic table.
Ans: The elements which have a tendency to gain electrons are known as non-metals. The tendency to gain electrons increases on moving across a period due to an increase in the nuclear charge and decrease in the atomic size. Hence, the non-metallic character increases across a period. As we move down the group, the non-metallic character decreases due to increase in the atomic size.