These come from atoms sharing their valence electrons. Because they are not ionic, they obviously are not consisted of ions; they are consisted of molecules held together by forces called Van der Waal’s forces which are not strong. Just like how we know how gases are spread out, solids are compact, and liquids are the slightly spaced out substances with no shape, it is the same with covalent compounds and Van der Waal’s forces; the forces are not strong enough to create strong solids however, so the solids are soft. The compounds have low density because of how spread out the molecules are in the substances due to the weak forces. Low melting points and boiling points are a characteristic of these bonds because it is easy for energy to break Van der Waal’s forces. Electricity doesn’t travel well through these bonds because they don’t have as good electric potential as ionic bonds.
Covalent bonds share electrons. In the first electron shell of hydrogen, there is one valence electron; the first electron shell has space for two electrons, so an extra electron will be attracted to the atom.. Another hydrogen atom has the ability to combine with that atom so that their electrons will combine to fill up the electron shell, creating H2 – a covalent bond.
Ionic bonds:
In ionic bonds, electrons transfer between atoms. Electrostatic forces hold atoms together after they lose or gain electrons and their charges change, making the atoms attracted to each other.
When a sodium atom gives the electron it has in its outer shell to a chlorine atom, which has one open spot in its outer shell, the sodium gets a positive charge from losing an electron and the chlorine gets a negative charge when it gains the electron from the sodium atom. An ionic bond is made because opposites attract!
Ionic bonds are made up of metals and nonmetals because they attract to each other due to the fact that metals lose their electrons and nonmetals are the opposite. Ionic compounds conduct electricity well, most likely because of the presence of metal, and dissolve rapidly in water. Their bond has stronger forces than covalent bonds, so they can resist temperature a little better; therefore, they have a higher melting point. It’s tougher to break their bond and they make crystalline atoms.
Metallic bonding:
Metallic bonding happens between metals. Because, according to the Electron sea model/Electron gas theory, metallic bonds are not aimed at any specific direction, their bonds are weaker than covalent bonds.
The metals give up their valence electrons easily and electrons move around empty orbitals in the metals without restraint, like the liberated movement of sea water or gas (how it gets its name), because of the lower energy. Positive metal ion layers and electrons that are drawn to each other are what form the bond. Size and charge of the metal ions along with the number of valence electrons determine how strong the bond between two metals will be.
Metals are malleable and ductile because of the weak metallic bonds. The metals we can hold in our hands, such as lead – which is a very flexible metal, are perfect examples of these bonds.
Picture: http://www.geo.arizona.edu/xtal/nats101/s04-18.html
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