Introduction:
The purpose of this lab was to study how atoms bonds, how electronegativity affects bonding, and the structures bonded atoms make. In this lab models of an atoms structure were made based on the formulas given. This lab illustrated the effects of electronegativity on bonding, the geometry of atoms, and how VSEPER was important for determining an atoms configuration. There are two types of bonding, ionic and covalent. In the lab, covalent bonding was the only type dealt with, Ionic compounds have a much greater difference in the electronegativity of their atoms, but molecular compound have little to no difference in the electronegativity of their atoms. In both types of bonding the octet rule applies. The octet rule means that atoms have an electron configuration to mimic the configuration of the nearest noble gas withal full orbitals. This means atoms need eight valence electrons, except in the case of Helium which only has two valence electrons. In the lab the balls used for atoms had holes in them representing electrons that needed to bond. Only once every hole had been filled the atoms would complete its octet, and have eight valence electrons. Atoms want eight valence electrons because this makes them extremely stable, they no longer need to bond. Nobel gases have their outer shell of valence electrons which makes them extremely stable, because they no longer need to bond. Atoms goal is to mimic the electron configuration of noble gases so they are stable and do not have to bond either. An ionic bond is a type of bond that includes a metal and a non-metal that loose. In ionic bonds, non-metals gain electrons in order to have a set of eight valence electrons, and metals loose electrons. Since ionic bonding requires that the atoms involved have unequal attraction for their valence electrons, an ionic compound must have atoms of atoms far apart on the periodic table. If atoms are far apart on the periodic table they will have a greater difference in electronegativity. In order for a bond to be ionic, atoms need to have a difference in electronegativity’s that is greater than two. When atoms make ionic bonds they get a charge. In an ionic bond, the atoms that lose in order to reach their octet, gain a positive charge. This positively charged ion is called a cation. In ionic bonds, the atom(s) that gain electrons in order to have a complete set of eight valence electrons gets a negative charge. Atoms that gain a negative charge are called anions. Ionic bonds are the bonds that form ionic compounds. Ionic compounds have a charge. Covalent bonds are bonds in which a pair of electrons is shared between two (or more) atoms in order to have a set of eight valence electrons. Covalent bonds can only take place between none-metals. Unlike ionic bonding where one atom losses electrons for another to have eight electrons atoms in covalent bonds share electrons so each atom has a complete set of eight valence electrons. Depending on the difference of the electronegativity of the atoms bonding, the polarity will be different. Polarity essentially means “unequal sharing”. If there is not a big difference in the electronegativity of bonded atoms, then the bond is non-polar. If there is a large difference in the electronegativity of two bonded atoms, (more then 0.5, but less than 1.9) then the bond is a polar covalent bond which means it’s unequal, but not ionic. Polar covalent bonds receive partial charges. The atom in the bond with greater electronegativity will receive a slightly negative charge, and the atom in the bond that is less electronegative will receive a slightly positive charge. These charges are what creates a dipole. Atoms are negatively charged on the outside which makes them repel each other and space themselves as far apart as possible. The term used for this is VSEPR, or valence shell electron pair repulsion theory. This theory is essential to the geometry of atoms because pairs of electrons
