number of valence electrons in si element

One of the ways that atoms obtain 8 electrons in their valence shell is to lose or gain electrons. The octet rule can be used to predict the charge on the monoatomic ions that form from the representative elements. The columns indicate, for the neutral form of the element, how many valance electrons are in the valance shell: the first column (Group IA) contains 1 valence electron, the second column (Group IIA) contains 2 valence electrons, etc., and the last column (Group VIIIA) contains 8 valence electrons. When focusing on the representative elements, the rows tell you which energy level contains the valence electrons: row 1 is the n=1 level, row two is the n=2 level, etc.

The periodic table also provides clues about an element's electronic structure. Here, isoelectronic ions and atoms are shown with the same color. Atoms lose or gain the number of electrons necessary to have an octet (to become isoelectronic with the nearest inert gas). Figure 3.8 in Raymond shows the representative elements:įigure 2 ( Figure 3.8 from Raymond ): Some common ions of representative elements. For example the far right-hand column contains gases which are all chemically inert. Originally the elements were arranged on the periodic table, from left to right, according to their atomic number, and in columns according to their chemical and physical properties. The periodic table reflects this situation. This is a statement of what is called the octet rule. so that each atom ends up with 8 electrons in their valence shell. They do this by reacting with one another to gain, lose or share electrons. Chemistry can be thought of as basically a consequence of all of the elements on the periodic table trying to achieve the same number of valence electrons as one of the inert gases. All of the other elements on the periodic table would like to be like an inert gas in terms of the number of electrons they have in their valence shell. The inert gases are called inert because they are very unreactive with themselves and other elements. Even if an energy level can hold more than 8 electrons, the most stable number, is 8. (Each energy level can contain up to 2 n electrons, where n is the energy level refer to Section 3.2 and Table 3.4 in Raymond). This is because the first energy level can only hold 2 electrons, whereas the other energy levels can hold 8 or more electrons. All of the inert gases have 8 valence electrons, except helium, which has 2. These elements, as a group, are are called the inert gases. The elements that have this number in their pure neutral forms are the elements in Group VIIIA. This happens be the most stable situation for an atom. It turns out that there is something special in nature about having eight electrons in the valence shell. In the electron dot structures used here, valence electrons are shown as dots. Representative elements in the same group have the same number of valence electrons. Note that the number of valence electrons that each element has is equal to its group number, e.g., elements in Group IA have one valence electron (one dot), elements in Group IIA have two valence electrons (2 dots), etc.įigure 1 ( Figure 3.6 from Raymond ): Valence Electrons. Figure 3.6 in Raymond uses Lewis electron dot structures to show the number of valence electrons in some of the representative elements. Together, these elements are referred to as the main group or representative elements. For our discussions we will focus on the elements in the first two columns on the left-hand side of the periodic table and the last six columns on the right-hand side of the table. These are the electrons found in the highest occupied energy level or shell for an atom of an element. In Section 3.2 the concept of valence electrons was introduced.

Number of valence electrons in si element