Chemical Bonds & Reactions

1. Chemical Bonds & Reactions

2. WORD SPLASH • Product • Reactant • Yields • Equation • Subscript • Compound • Catalyst • Element • Ionic • Covalent • Bond • Stable • Synthesis • Decomposition • Replacement • Write a story using the words on the list • Underline each word used • Circle words you’ve never heard in RED • Circle words you’re familiar with but unsure of in YELLOW • Circle words you know well in GREEN

3. BONDING • Valence Electrons - all the electrons on the outer-most energy level (ROMAN NUMERAL)

4. BONDING • Chemical Bond – a force that holds two or more atoms together when their outer-most energy levels become filled by each other. • Creates a chemical reaction

5. Stable – when all of an atom’s energy levels are filled and it can no longer react • Stable atoms become charged • Unstable atoms have empty spaces on their energy levels and have no charge because their e- balance out with p+

6. How Do Atoms Bond?? • Ionic Bond – when an atom becomes stable by giving or taking (exchanging) electrons from another atom. • Ion-an atom that has gained or lost electrons and has a charge

7. Cation –gives away e-, has a positive charge • clue to remember (ca+ion) • Anion- takes e-, has a negative charge • clue to remember(/-\nion) • Ions with opposite charges bond together – opposites attract

8. An atom’s charge is neutral if its p+ and e- are balanced • Atoms are usually unstable if they are neutral (except column VIII)

9. Covalent Bond – when 2 atoms fill their outer energy levels by SHARING a pair of electrons • Both atoms keep their electrons on the outer ring • Charge doesn’t change, atoms stay neutral AND become stable

10. Chemical Formulas • Chemical Formula- a way to write the name of bonded atoms (compounds) • Ex. NaCl: uses Chemical Symbols • Compound - _____________________

11. Chemical Formulas • Chemical formulas show how many of each atom are in the compound • Subscript- a number written to the lower right of a chemical symbol in the chemical formula • DO NOT WRITE ONE (1)! • Ex. H20, NaCl, C6H1206

12. Chemical Reactions • Chemical Reaction- when new substances are created from chemical bonds being formed or broken • These new substances have new properties and are often compounds! • Two parts: • Reactants – what you start with (what reacts) • Products – what you end with (what is created)

13. Conservation of Matter - matter can’t be created or destroyed in a reaction • The items and the amount of items you start with MUST be the same as what you end with • LIKE BAKING A CAKE • Catalyst – changes how reactions happen, doesn’t actually react • Speed up or slow down

14. Chemical Equations • Chemical Equation- written reaction • Adding zinc to hydrochloric acid looks like: Zn + HCl  ZnCl2 + H2 • Reactants (start)  products (end) •  is like an equals sign “yields”

15. Types of Reactions • Synthesis – 2 or more substances react to form a new compound • 2Na + Cl22NaCl • Decomposition – One substance breaks down during a reaction • 2NaCl  2Na + Cl2 • Replacement – one element takes over the spot of an item in a compound • CuSO4 + Fe FeSO4+ Cu • Combustion – reaction involving oxygen that produces light and heat. • CH4 + 2O2 CO2 + 2H20