1. Chemistry Chapter 8 Notes 3

2. Review Compounds Can all be represented by chemical formulas Are connected by chemical bonds Ionic Metallic Covalent Compounds have different properties than the elements that make them up …

3. Review Ionic Compounds Made up of a metal + nonmetal (cation + anion) Attraction between positive and negative charge They come together to balance out the positive and negative charge Each chemical formula = formula unit

4. Metallic Bonds Attraction between one atom’s positive nucleus and another atoms negative electrons pack the atoms closely together The outermost energy levels of the atoms overlap because they are so close Electrons can move from atom to atom atoms can slide past each other without breaking the bonds

5. Metallic Bonds Electron Sea Model All metals contribute their valence electrons to form a “sea” of electrons The e- are not held by any specific atom (they travel from atom to atom) Delocalized e- = because they are free to move Metallic Bonds = attraction of a metallic cation for delocalized electrons

6. Metallic Bonds

7. Properties Moderately high melting and boiling points Malleable Ductile They are bendy because the atoms can slide past each other without breaking the bonds Good conductors of heat and electricity All are due to the ability of the electrons to move past each other The solid is a crystal lattice type solid

8. Alloys Substitutional Alloy Atoms of the original metallic solid are replaced by other metal atoms Ex. Sterling silver = silver + copper Make it more durable Interstitial Alloy Small holes in a metallic crystal are filled with smaller atoms Carbon steel – holes in iron fill with carbon Make it stronger