1. Chemical Bonding Science Investigations

2. What is a chemical bond? Electrical attraction between the nucleus of one atom and the valence electrons of another An element’s properties are due to its valence electrons What diagram shows the valence electrons of an atom?

3. Octet Rule Atoms will gain/lose electrons through bonding to have 8 valence electrons to be stable like a noble gas Exceptions: Helium and Hydrogen only need two valence electrons

4. Ionic Bonds A metal atom gives electrons to a nonmetal atom Rule of thumb: A metal (alkali or alkaline earth) + nonmetal = ionic Examples: LiF, CaO

5. Covalent Bonds Atoms share electrons Two types: Polar Covalent: Unequal sharing of electrons Nonpolar Covalent: Equal sharing of electrons

6. Covalent Bonds Rule of thumb: Two nonmetal atoms that are different = polar covalent Ex.: CO 2, H 2 O Two nonmetal atoms that are the same = nonpolar covalent Ex.: H 2

7. Metallic Bonds Bond between 2 metal atoms Electrons are shared equally between all metal atoms and are free to move from atom to atom (sea of electrons) This makes metals good conductors of heat and electricity