Consider sodium: in its elemental form, it has one valence electron and is stable. It is not impossible to violate the octet rule. When atoms form compounds, the octet rule is not always satisfied for all atoms at all times, but it is a very good rule of thumb for understanding the kinds of bonding arrangements that atoms can make. The trend that atoms like to have eight electrons in their valence shell is called the octet rule. ![]() For whatever reason, having eight electrons in a valence shell is a particularly energetically stable arrangement of electrons. Either atoms gain enough electrons to have eight electrons in the valence shell and become the appropriately charged anion, or they lose the electrons in their original valence shell the lower shell, now the valence shell, has eight electrons in it, so the atom becomes positively charged. The astute reader may have noticed something: Many of the ions that form have eight electrons in their valence shell. In Section 8.1 "Lewis Electron Dot Diagrams", we saw how ions are formed by losing electrons to make cations or by gaining electrons to form anions. Demonstrate electron transfer between atoms to form ionic bonds.Before we discuss how electrons interact, we need to introduce a tool to simply illustrate electrons in an atom.Įlectron Transfer: Ionic Bonds Learning Objectives But how do atoms join together? Ultimately, it all comes down to electrons. How do atoms make compounds? Typically they join together in such a way that they lose their identities as elements and adopt a new identity as a compound. Silicon dioxide and boron nitride have some similarities, but neither of them comes close to the ultimate hardness of diamond. There are other substances that have similar bonding arrangements as diamond does. Not only does a person have to break many connections at once, but also the bonds are strong connections from the start. There are stronger interactions known, but the carbon-carbon connection is fairly strong itself. Breaking a diamond means breaking every bond at once.Īlso, the bonds are moderately strong. This three-dimensional array of connections extends throughout the diamond crystal, making it essentially one large molecule. Four is the greatest number of bonds that is commonly made by atoms, so C atoms maximize their interactions with other atoms. In a perfect diamond crystal, each C atom makes four connections-bonds-to four other C atoms in a three-dimensional matrix. What is special about this element that makes diamond so hard? ![]() Diamond is the hardest natural material known on Earth.
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