Covalent bond

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Covalent bonds are chemical bonds atween twa non-metal atoms. Aen exemple is watter, whaur hydrogen (H) an oxygen (O) bond thegither tae mak (H2O). Sin they are baith non-metals—that need tae gain electrons—they hae tae share, sicweys thair ooter shells cross over in order tae hae a full ooter shell. A full ooter shell haes aicht electrons. The electrons in this ooter shell are cawed valence electrons.

The nummer o valence electrons is decidit by the bouch o the atom. Electrons orbit an atomic nucleus in the same kind o airt that planets orbit starns. Thare are layers o paths aroond an atomic nucleus. The first layer always contains anely twa electrons, while the layers ahint for ordinar conteen up tae aicht.

For exemple, gin an atom contained aicht tot electrons, the first twa wad orbit verra close tae the nucleus, the neist 6 wad orbit a wee faurer awa. Ilka atom faut a "full" ooter shell. That is tae say, it faut the nummer o electrons in the ootmaist layer tae be as heich as they cannin be. Sin maist atoms' ooter shells cannin support up tae aicht electrons, this is the nummer o electrons maist atoms faut in thair ooter shell. In this exemple, the atom had aicht total electrons, an sax in the ooter shell. Acause thare are fewer as aicht electrons in the ooter shell, the atom will faut tae "fill" the pairts for twa electrons wi electrons borraed frae anither atom. Whan an atom "borraes" electrons wi anither atom, a covalent bond is creautit.

Wi watter the oxygen atom shares one electron wi ilk hydrogen atom an the hydrogens an aw share one: this means that the hydrogen atoms hae twa ilk an the oxygen atom haes aicht.

Types o Covalent bond Covalent bonds cannin be spelt intae twa groups. Semple an "Giant". Awtho they are baith alike, thare are some raither large distinguishing factors. For exemple, "Giant" Covalent bonds hae relatively heich melting an boiling points, whaurby Semple Covalent bonds hae a relatively laich melting an boiling point. This is acause o the inter-molecular forces o attraction. Wi "Giant" Covalent bonds, the bonds atween layers are verra strang, Diamond is ane exemple o "Giant" Covalent bond o carbon. Houaniver, wi a semple Covalent bond, the bonds atween the atoms hae a strang inter-molecular bond, but thare are no bonds atween the molecules, which is why it haes a relatively low melting an boiling point.

Covalent bonds are less strang as ionic bonds, an hae a lower melting point. They are an aw kent tae be poor conductors o electricity an heat (except silicates an carbides).