Here is some helpful information: PROTON, NEUTRON and ELECTRON HANDOUT: 1.Atomic Number= # of Protons 2.# of Protons= # of Electrons 3.Atomic Mass= Protons + Neutrons (Atomic Mass and Atomic Weight are the same thing)

Elements n Element= a pure substance that is made up of 1 type of atom. n Elements are represented by a symbol (1 or 2 letters). –C stands for carbon. –Na stands for sodium n Periodic Table= arranges elements according to the # of protons an atom has.

Atoms n Atoms are made of subatomic particles: n Protons (P) (+ charge) n Neutrons (N) (No charge) n Electrons (e-) (- charge) n The protons and neutrons are bound together in the dense nucleus. n Electrons move in the space around the nucleus.

Atoms n NUCLEUS= center of the atom. Determines the weight of the atom. (# of protons + # neutrons) n PROTONS: n Positive charge (+1) n Atomic mass =1 (amu) n atomic #= # of protons in an atom. n NEUTRONS: n No charge n Atomic mass=1 (amu) n # of neutrons is determined by comparing the atomic number to the atomic mass.

Atoms n ELECTRONS: Negative charge= -1 n Move in orbits (shells) n Each orbit has a maximum # of e- it can hold: 1 st shell: 2 e- 2 nd shell: 8 e- 3 rd shell: 8 e- n Atoms are NEUTRAL because the subatomic particles have equal but opposite charges. n # of protons = # electrons

n Krypton's atomic number= 36 n Krypton has 36 protons in its nucleus. n Adding or removing protons from the nucleus of an atom creates a different element. Atoms

n Atomic Mass #= (# of Protons) + (# of Neutrons) n 84 = (# of Protons) + (# of Neutrons) n 84 = 36 + (#of Neutrons) n 48= #of Neutrons Atoms

Isotopes n Isotopes: different forms of the same element. n They have the same: - Atomic # -# of Protons - # of Electrons n They have different # of Neutrons n Ex. Carbon-12 (6 neutrons), Carbon-13 (7 neutrons), & Carbon-14 (8 neutrons)

Some of the larger elements have isotopes that are unstable. They slowly change into a more stable form by releasing neutrons. This process releases radioactive particles and energy too. These isotopes are considered radioactive. Isotopes and Radioactivity

Radioactive isotopes have many functions in science: 1) “markers.” 2) medical procedures. 3) treatment (Cancer patients receive radiation to kill the cancer cells.) Long-term exposure or exposure to high-energy radiation can cause diseases such as cancer. Isotopes and Radioactivity

Atoms n ELECTRONS: Negative charge= -1 n Move in orbits (shells) n Each orbit has a maximum # of e- it can hold: 1 st shell: 2 e- 2 nd shell: 8 e- 3 rd shell: 8 e- n Atoms are NEUTRAL because the subatomic particles have equal but opposite charges. n # of protons = # electrons

Am I “happy”

Valence e- n Each orbit has a maximum # of e- it can hold: 1 st shell: 2 e- 2 nd shell: 8 e- n Outer e-= Valence e- n To be “happy” atoms want to fill up their outer shell. –Share e- –Add/lose e- OCTECT RULE- They want 8 e- in outer shell

CARBON Chlorine Hydrogen Phosphorous

Compounds & Bonding n Compounds= Chemical combination of 2 or more elements. n The atoms in compounds are held together by chemical bonds: –Ionic & Covalent Bonds n Ionic bonds = transfer electrons –The transfer of electrons creates charged atoms called ions.

Atoms n When an atom loses an electron it will have more protons than electrons = positive charge (CATION): n Li +, Na +, n Mg 2+,Ca 2+ n (usually metals) n When an atom gains an electron it will have more electrons than protons= negative charge (ANION): n Cl -, Br -, I - n S 2- n (usually nonmetals) Ion Cat Video!! Cation and Anion Practice Worksheet!!

Compounds & Bonding n Covalent bonds= share electrons –Compounds with covalent bonds are molecules. –There can be single, double, or triple bonds depending on the # of electrons shared

Covalent Bonds n NonPolar Covalent Bonding= equal sharing of e- n Polar Covalent Bond= If one atom in the bond attracts e- more than the other atom. –UNEQUAL SHARING OF e- n Electron rich side= slightly negative end n Electron deficient side = slightly positive H2O Love Story Video (part 1)

2-2 Water Molecule n Water molecule (H2O) is a neutral molecule. n Protons: (H) 1 + (H) 1 + (O) 8 = (H2O) 10 protons n E-: (H) 1 + (H) 1 + (O) 8 = (H2O) 10 electrons

n What has a stronger pull for electrons, the H or the O? n There is a greater probability of finding the shared electrons near the O than near the H. n Polar covalent bond = unequal sharing of electrons. Polarity What will the partial charges be on the O & H? n Oxygen= Slightly Negative n Hydrogen= Slightly Positive 8P 8N 1P 0N 1P 0N

Hydrogen Bonds n Because of the partial (+) and partial (-), polar molecules can attract each other. n Hydrogen Bonding= The attractive force between one water molecule and another. (MUST involve a Hydrogen atom) n The H in one water molecule is attracted to the O in another Water molecule. POLARITY

n A single water molecule can be involved in 4 hydrogen bonds. n Multiple hydrogen bonding is responsible for water’s properties: n Cohesion, Surface Tension and Adhesion. Hydrogen Bonds

n Cohesion = waters attraction to other water molecules because of polar properties –Surface tension = allow objects that are more dense than the liquid to be supported on the surface of the liquid without sinking. –Ex. insects walking on a ponds surface. Water- Cohesion

Water- Adhesion n Adhesion = water attracted to other materials. Ex: Water in a straw, water moves through trees this way n Water is attracted to other material and then cohesion holds the water together as it rises.

pH Scale n A water molecule can react to form ions. n H 2 O  OH- + H+ n The pH Scale- indicates the [H+] ions in a solution. n The pH Scale ranges from 0-14 n A pH of 7= [H+] = [OH-] (neutral) Pure water n Solutions with a pH below 7 is ACIDIC because they have more H+ ions. n Solutions with a pH above 7 is BASIC because they have more OH- (hydroxide) ions.

pH Scale n Low pH= Acidic n High pH= Basic

pH Scale n Acids= compounds that form/release H+ ions in solution. n Contain a higher [H+] ions than pure water. n pH values below 7. n Strong acids have a pH range from 1-3. n Example: hydrochloric acid (HCl) dissolves in water as follows: HCl  (H 2 O)  H + + Cl -

pH Scale n Bases= compounds that form/release OH- ions in solution. n Also known as ALKALINE n Contain a lower [H+] ions than pure water. n pH values above 7. n Strong bases have a pH range from n Example: sodium hydroxide (NaOH) dissolves in water as follows: NaOH  H 2 O  Na + + OH -

pH Scale

It will depend on the number of molecules that break apart when the acid or base dissolves in water.

If ALL the molecules of an Acid break apart and release H+= STRONG If only a few molecules of an Acid break apart and release H+= Weak

pH Scale n The pH of most cells in the human must be kept between n Controlling the pH is important for maintaining the homeostasis n BUFFERS– weak acids or bases that can react with strong acids or bases to prevent sudden changes in pH. 1) bicarbonate buffer system 2) phosphate buffer system 3) protein buffer system *If they find themselves in a solution with a lot of H+ floating around (an acid), they act as bases and suck up the excess H+ *And if they find themselves in a solution lacking free H+ (a base), they donate their H+ to the solution.

Solutions and Suspensions n Mixture-a material composed of two or more elements or compounds that are physically mixed together, but not chemically combined. n 2 Types of Mixtures that are made with water: n Solutions and Suspensions

Solutions Cl - Water Cl - Na + Water Na + n Solution= a mixture of two or more substances in which the molecules of the substance are evenly distributed. (particles dissolve) n Example: Salt Water n solute-the substance that is dissolved: Table Salt n solvent-the substance in which the solute dissolves: Water

Suspensions n Suspensions- When materials do not dissolve when placed in water but break into pieces that do not settle out. n Particles in suspensions are larger than particles in a solution. n Particles are suspended (they will NOT dissolve). n Example: Blood, Italian Dressing, Oil and Water & Sand in water.

ALIEN JUICE BAR: Testing your Acid and Base Knowledge

Periods and Groups Periods go from left to right Periods go from left to right Groups go up and down Groups go up and down

Bohr Models RULE Show just electrons with energy levels Show just electrons with energy levels 1 st level holds 2 e- 1 st level holds 2 e- 2 nd level holds 8 e- 2 nd level holds 8 e- 3 rd level holds 18 but is stable at 8 e- 3 rd level holds 18 but is stable at 8 e RULE!! RULE!! Must fill an energy level to capacity before moving to the next energy level Must fill an energy level to capacity before moving to the next energy level

Bohr Models

Lewis Dot Structure Show Valence e- ONLY!! Show Valence e- ONLY!! top-bottom-left right and then begin to pair e-. top-bottom-left right and then begin to pair e-.