chapter 12 chemical bonding

1. chapter 12chemical bonding

2. Essentially everything we see around us, natural or man-made, compounds or elements, has atoms bonded with atoms • Hard or soft, solid, liquid, or gas; these properties are determined by bonding • Their structures play the major role in chemical rxns all around us • The way they’re bonded determines structure

4. 12.1 types of chemical bonds • Bond: a force that holds groups of two or more atoms together and causes them to function as a unit • They can do this in several ways!

5. These substances are called ionic compounds • Ionic bonds involve the gain, loss or exchange of electrons • They generally form between metals and nonmetals, why?

6. Nonmetals, with their higher electronegativity, are able to strip electrons from metals (metals have lower ionization energies) • Ionic bonds are strong

7. metals form ions by losing electrons • nonmetals gain electrons • there can also be a transfer of electrons • and the result is two things that are of opposite charge and therefore attracted to each other

8. When the atoms are reconfigured into ionically bonded substances, they are more stable and energy is released

9. Consider table salt (NaCl) • When the water in salt water evaporates away, the Na+ get together with the Cl- to form NaCl • This closely packed collection of oppositely charged ions is an example of Ionic bonding

10. Covalent Bonds What if the atoms are both nonmetals with similar electro-negativity? • When these two particles get close, the e- of one are attracted to the p+ of the other; the e- (or p +) of one are repelled by the e- (or p +) of the other

11. Covalent Bonds • If they are most stable at a distance where their e- shells overlap, a bond may form

12. Covalent Bonds • This is a covalent bond because outer shell (valence) electrons are shared by both atoms

13. Ionic/ covalent bond comparison

14. Questions?