3.1 Matter And Substances I. Atom A. Def- the __________ _______of matter that cannot be broken down by chemical means. B. Atomic structure 1. Protons = _______________ 2. Neutrons = ______________ 3. Electrons = ______________

1. Made up of all the same __________ a. ex- _________________ 4. Protons & Neutrons have same ______ and are found in the ____________ 5. Electrons are _________ the mass of protons & neutrons. Found in electron __________ around the nucleus. C. ______________ 1. Made up of all the same __________ a. ex- _________________ 2. __________ have extra __________ a. makes atom ________, no change in overall __________.

II. Chemical ___________ A. ___________ electrons 1. Electrons in the __________ energy level. 2. This level wants to fill to _____ electrons. B. ______________ 1. Made up of ____ or more elements

C. ___________ Bonding 1. The _________ of electrons 2. A ___________is a group of atoms held together by a _________ bond 3. Not all substances that have covalent bonds are___________. a. ____ covalent bond, not a compound b. _______ covalent bond, compound

D. __________ Bonding 1. ________ or _______electrons 2. ion – ____________ or __________ charged group of atoms. 3. ionic bond is the attractive force between ___________ charged ions. 4. ex- ____________ (NaCl) a. ________(Na+) - silver, soft metal that explodes in water b. __________(Cl-) - green toxic gas

III. ___________ A. Molecules with partial charges on __________ ________ are polar. B. _____________ 1. ________ can dissolve polar molecules a. ex.- _________, _________ 2. ____________ molecules do not dissolve in water. They instead ___________ together. a. ex.-______, __________, ________

C. Hydrogen Bonds 1. Stronger than attractions between other molecules but not as strong as a covalent bond. a. ex.- 2 strands of DNA are held together by hydrogen bonds between bases.