Gold (Au): +1, +3 Construction of Molecules.Next, we show you some examples of the valence table. Each group has a specific valence associated with it. In it, the elements are organized in columns called groups. To determine the valence of an element, we can consult the periodic table. These positive ions are highly reactive and tend to form ionic bonds with anions (negatively charged ions) to achieve electronic stability. For example, alkali metals such as lithium, sodium, and potassium have a valence of +1, which means that they can lose an electron and form positive ions with a charge of +1. When an atom has a positive valence, means that it has a tendency to lose electrons and form cations. Therefore, oxygen has a valence of II, which means that it can form bonds with two hydrogen atoms. For example, oxygen has an electron configuration of 1s^2 2s^2 2p^4 and needs to gain two electrons to reach the nearest noble gas configuration, which is the neon configuration (1s^2 2s^2 2p^6). Valence is generally expressed in terms of the number of electrons an atom you can win, lose or share to reach the most stable electronic configuration, which is the nearest noble gas configuration. It represents the maximum number of bonds that an atom can form and is related to the electronic configuration and structure of the outer shell of electrons. Valence is a fundamental property of atoms and chemical groups that determines its ability to form chemical bonds with other atoms. The electrolysis of water using a battery: a fundamental process to obtain hydrogen and oxygen from the decomposition of water by means of an electric current. Hydroxide ions (OH-) present in the water are attracted to the cathode, where they gain electrons and become molecules of water and oxygen gas (O2): 4H2O(l) + 4e-> 2H2(g) + 4OH-(aq) Hydrogen ions (H+) present in the water are attracted to the anode, where they lose electrons and are released as hydrogen gas (H2): 2H2O(l) -> O2(g) + 4H+(aq) + 4e-Īt the cathode, reduction of water occurs. When an electrical current is applied to the cell, two simultaneous reactions occur at each electrode.Īt the anode, oxidation of water takes place. In the electrolytic cell, the positive electrode is called anode, while the negative electrode is known as cathode. This reaction is carried out in a device called electrolytic cell, consisting of two electrodes immersed in water and connected to a direct current source. The electrolysis of water is a chemical process by which water breaks down into its basic components, hydrogen (H2) and oxygen (O2), using an electric current. In this article, we will explore the valence table of all the elements on the periodic table, understanding how valence is determined and how this information is useful in the construction of molecules.
which determines its ability to combine with other elements to form chemical compounds. One of the essential characteristics of elements is their valence. The periodic table is a fundamental tool in chemistry, since it provides us with valuable information about the elements and their properties.
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