The Chemical basis of Life

 Anything that occupies ___________ and has _________. ◦ Mass is commonly measured by how much something weighs ◦ Can exist as:  ____________

 Element- The simplest form of matter that cannot be broken into smaller substances by natural means. ◦ Hydrogen, Oxygen, Carbon, and Nitrogen make up 96% of the matter in an animal’s body. ◦ Elements are referred to by a ____________ ______________and are organized in the Periodic Table of Elements.

GROUP  PERIOD 

 Major Elements ◦ Oxygen(O) ◦ Carbon(C) ◦ Hydrogen (H) ◦ Nitrogen (N)  Minor Elements ◦ Calcium (Ca) ◦ Phosphorus(P) ◦ Potassium(K) ◦ Sulfur(S) ◦ Sodium(Na) ◦ Chlorine (Cl) ◦ Magnesium (Mg)

◦ Silicone (Si) ◦ Aluminum (Al) ◦ Iron (Fe)* ◦ Manganese (Mn) ◦ Fluorine (F) ◦ Vanadium (V) ◦ Chromium (Cr) ◦ Copper (Cu)* ◦ Boron (B) ◦ Cobalt (Co) ◦ Zinc (Zn)* ◦ Selenium (Se) ◦ Molybdenum (Mo) ◦ Tin (Sn) ◦ Iodine (I)*

 The ___________ unit of an element that retains the unique properties of that element.  Composed of 3 subatomic particles: ◦ _________________

 Protons and Neutrons are found in the __________________.  Each proton and neutron has an atomic mass of ~1. ◦ Together protons and neutrons determine the atomic ____________ of the atom. ◦ The atomic _____________ of an element is equal to the number of protons in that element.  Protons have a ______________charge.  Neutrons have __________ charge and are considered neutral.  Electrons have a ________________ charge.  Net charge of atoms are neutral because have equal numbers of protons and electrons.

 Tiny particles that remain in constant motion around the ________________.  So tiny that their mass does not contribute to the atomic _____________ of the atom.  Electrons have a ____________charge.

 The atomic number of an atom tells us how many ______________ it has. This number cannot change as it is what makes each element unique.  If an atom loses or gains an ______________ in an attempt to fill its outermost electron shell then it becomes positively or negatively charged, thereby becoming an __________.  If an atom has a different number of neutrons, they are called ________________ of the element

e-e- Na atom 11electrons, 11protons Na + ion 10electrons, 11protons

 “Pathways” around the nucleus where electrons orbit ◦ There are one or more shells surrounding the nucleus, depending on the # of electrons. ◦ An electron’s energy level determines which shell it will inhabit. ◦ Lower energy electrons exist in the 1 st electron shell (closest to the nucleus) ◦ Higher energy electrons are in the 2 nd shell

◦ Only a certain number of electrons can be on each pathway/shell ◦ First shell can contain two electrons. ◦ Second shell can contain eight electrons.

 If the outermost shell is not full, then an atom will be more active in an attempt to fill it.  Helium and Neon have full electron shells so are considered chemically inactive/inert.  Atoms are most stable when their shells are full.  Atoms with incomplete shells are constantly trying to find electrons to complete their outer shell.

 ___________________- form when two or more atoms are joined together by chemical bonds.  Molecule of the __________________-two or more atoms of the same element are joined together.  Example: Oxygen, O 2  ________________ -two or more atoms from different elements are joined together.  NaCl, CO 2

 Chemical bonding means that atoms are _________________ or __________________ electrons. ◦ By doing this, each atom can be sure that its outermost shell is full.  Atoms are constantly trying to become more stable.  Types of chemical bonds: ◦ _________________, _________________, _________________

 Bonds formed when atoms ______________ electrons.  Classified depending on how many electrons are being shared. ◦ single covalent bond: ______ electron is shared ◦ double covalent bond: ______ electrons are shared ◦ triple covalent bond: ______ electrons are shared  The shared electrons spend part of their time in the electron shell of each of the atoms.

Polar Water Molecule  Shared electrons in a covalently bonded molecule may spend more time near one atom than the other  Shared electrons in water molecule spend more time near the __________atom than __________ atoms ◦ Poles are created  Gives molecule a slight _________ charge on H side of molecule and slight _________charge on O side of molecule

 Formed when electrons are _________________ from one atom to another  usually from an atom with one or two electrons in the outer shell to an atom that needs one or two electrons to fill its outer shell ◦ Transfer causes a ______ charge on the atom that gave up the electron and a ____________ charge on the atom that receives the electron. ◦ Since opposites attract, the two atoms “stick” together through electrostatic attraction.

 ______________Ions with a net positive charge. ◦ Ca+, K+, Na+  _______________Ions with a net negative charge. ◦ Cl-, F-  Ions are important in contraction of muscle fibers, transmission of nerve impulses, and maintenance of water balance.

 ________ bond between hydrogen atoms already ______________ bonded in a molecule to oppositely ______________ particles. ◦ (F,N,O)  Mostly formed between separate molecules, but can be formed between parts of the same large molecule (proteins and DNA), which can act to stabilize the molecule’s shape

 The formation and breaking of chemical bonds.  Require energy input or release of energy.  Chemical Equation- reaction is described in written form. ◦ X + Y → Z ◦ (reactants) (products) ◦ Arrow indicates direction of the reaction

 1. _______________ Reaction- new and more complex molecule is made from multiple, simpler chemicals. X + Y -> XYO + O -> O 2  2. ___________________ Reaction- single complex chemical is broken down into multiple, simpler chemicals. XY -> X + Y2H 2 O -> 2H 2 + O 2  3. ________________ Reaction- certain atoms are exchanged between molecules. Combination of synthesis and decomposition reaction. WX + YZ -> WY + XZ NaCl + AgNO3 -> NaNO3 + AgCl +