Honors BIO 9/4 (B Day) & 9/6 (A Day) OBJECTIVE: Students will be able to: Describe chemical compounds Compare and contrast chemical bonds Create a representation of the water molecule DRILL: Draw an atom of Fluorine (F), labeling its subatomic particles.

Isotopes Atoms of same element have same # of protons (atomic #). Isotopes: atoms of same element with different #s of neutrons (affects mass).

Isotopes All have same # of electrons – same chemical properties Atomic Mass = weighted average of all isotopes of an element. Some isotopes are radioactive (nuclei are unstable, decay at constant rate) – Carbon dating – Detect and treat cancer – Kill bacteria that spoil food – Chemical tracers

Chemical Compounds How are compounds different from elements? – Properties of compounds are very different than properties of elements that make them up How are compounds made? – Combination of two or more elements, using chemical bonds – Chemical formula = shorthand – NaCl

Chemical Bonds What are the main types of chemical bonds? – Ionic – Covalent How are bonds made? – Valence (outer energy level) electrons are shared

Ionic Bonds 1 or more e- are transferred from one atom to another Loses e-, becomes positively charged Gains e-, becomes negatively charged Charged particle = ion Opposites attract = Ionic Bond Vowels O & I

Ionic Bonds Ionic bonds form between sodium and chloride to form NaCl, table salt.

Ionic Bonds Na atom loses one valence e- to become Na+

Ionic Bonds Cl atom gains one valence e- to become Cl-

Covalent Bonds Molecule = atoms are joined by covalent bonds. Water Oxygen Hydrogen

Ionic vs. Covalent Bonds Create a Thinking Map Comparing the two types of chemical bonds

FAB BIO VOCAB #2 Determine the definition (in your own words) of the following vocabulary words, along with a symbol, picture of icon. Use your background knowledge, or refer to the text. – Compound – Ionic Bond – Covalent Bond – Ion – Molecule