HOW CHEMISTRY IS CRUCIAL TO LIFE To understand how chemistry is crucial to life, is to understand… Atoms Molecules Bonding Compounds

All living things are made of the same basic building blocks. Chemistry All living things are made of the same basic building blocks. Atom: The smallest building blocks of matter. *They cannot be divided into smaller substances by ordinary (natural) processes. Roughly 100 different kinds of atoms

Protons (positive [+] charge) Neutrons (no[0] charge) 1 H Parts of the Atom Nucleus: small central part of the atom that contains both protons and neutrons. Sub Atomic Particles Protons (positive [+] charge) Neutrons (no[0] charge) Electrons: (negative [-] charge) Negatively charged particles that orbit the outside of the nucleus Atoms: in their normal state are electrically neutral (Same number of protons in the nucleus as electrons orbiting the outside

…ATOMS MOST FAMOUS ATOM TO A BIOLOGIST IS CARBON! * To be defined later MOST FAMOUS ATOM TO A BIOLOGIST IS CARBON! Carbon is found in many different *compounds. It is in the food you eat, the clothes you wear, the cosmetics you use and the gasoline that fuels your car Carbon is the sixth most abundant element in the universe In addition, carbon is a very special element because it plays a dominant role in the chemistry of life. Why, because it has incredible *bonding capabilities

Atomic Number: Is the number of protons in the nucleus (If the atom is in its normal state it also represents the number of electrons that orbit the outside) 1+ 8+

Atomic Mass The sum of the protons and neutrons in the nucleus. Why don’t we count electrons?

Energy Levels 1st level can hold 2 electrons 2nd level can hold 8 electrons 3rd level can hold 8 electrons If an atom has a filled outer most energy level the it is said to be a stable atom and will not form bonds with other atoms. Ex) Noble gases (He, Ne, Ar, Kr, etc.)

If the outer most energy level of an atom is not filled then it is said to be unstable and it will form bonds with other unstable atoms to become stable For example, Covalent or Ionic Bonds

Isotopes The same type of atoms that have different numbers of neutrons Varieties of atoms that are structurally the same but have a different number of neutrons. *Same Atomic Number but Different Atomic Mass ex) Oxygen 16(16O) Atomic # = 8, Mass # = 16 (8 neutrons) Oxygen 17(17O) Atomic # = 8, Mass # = 17 (9 neutrons) Oxygen 18(18O) Atomic # = 8, Mass # = 18 (10 neutrons) What is a radioactive isotope? It is an atom that has an unstable nucleus and it emits charged particles and transforms the atom to an atom of another element. Carbon 14(14C) Nitrogen 14(14N)

Elements Element: Substances that are made up of only on kind of atom. Ex) A chunk of Au (Gold) or Ag (Silver)

ELEMENTS

…ELEMENTS The periodic table lists all known elements They are classified based on their atomic number, a.k.a. number of protons An element is an atom (one type of) The element hydrogen is made of hydrogen atoms The element carbon is made of carbon atoms

Compounds Compound: Two or more atoms are bonded together. (Definite Proportions) Ex) Water (H2O) or Carbon Dioxide (CO2)

Covalent Bonds Form between the same or different types of atoms to form a molecule. Two or more unstable atoms Sharing of Electrons to form a stable molecule. Become stable by filling the outermost energy level (H2O)

MOLECULE A group of atoms held together by a covalent bond Remember me from Earth Science SiO44-

Diatomic Molecules Atoms that react with like atoms Hydrogen Gas Oxygen Gas Nitrogen Gas Most gases react this way

ION An atom that has lost or gained a(n) electron(s). Giving it a charge other than neutral Memorable examples… Ca2+ Na+ Cl-

Ionic Bonds Gaining or Losing an electron to fill the outermost energy level. Results in stable atoms that are now charged ions. The charged ion will form an electrical attraction (Ionic Bond) between oppositely charged ions Yields + -

Ionic Bonds Opposites attract to form compounds ex) magnets + -

Chemical Formulas Atoms combined in definite proportions. ex) Water 2 hydrogen and 1 oxygen atoms Glucose 6 carbons, 12 hydrogen, and 6 oxygen atoms *Each Atom/Element is represented by its chemical symbol (H2O) (C6H12O6)

Structural Formula Shows the number and types of atoms as well as how each atom is bonded together Covalent bonds are represented by lines between atoms One line indicates the sharing of one pair of electrons, 2 lines indicates the sharing of 2 pairs of electrons, etc.

Chemical Reactions All compounds are made of a combination of atoms bonded to one another When bonds between atoms are broken, different substances are formed “chemical reaction” Reactants: substances before the reaction takes place Products: new substance yielded after the reaction

Cell Respiration and Photosynthesis C6H12O6 + 6O2 6 CO2 + 6 H20 + Energy C6H12O6 + 6O2 6 CO2 + 6 H20 + Energy