Elements and Periodic Table Bonding, Compounds, Periodic Table

What does the periodic table tell me? Element symbol Atomic number: number of protons (and usually electrons, neutrons) Atomic mass: the average of all the isotopes’ mass What type of element it is (metal, nonmetal, etc) What elements can bond together (valence #) In what ratio elements bond (oxidation #)

Reading the Periodic Table: Elements Atomic number 16 Element symbol 32.06 Atomic mass

Types of Elements Metals: usually shiny, conductors, malleable, ductile, solids at room temperature. On left side of periodic table Non-metals: gas or brittle solid at room temperature, insulators. On right side of periodic table. Metalloids: have properties of both metals and non-metals. Between metals and non-metals.

Three types of Elements

Things to remember with symbols They are either one or two letters. Only the first letter is capitalized! Some symbols are based on the Latin name Some of the newest symbols use three letters until they are renamed (the atomic number in Latin)

Element symbols you need to know Gold Au Chlorine Cl Silver Ag Sodium Na Iron Fe Hydrogen H Lead Pb Helium He Copper Cu Carbon C

More element symbols Potassium K Neon Ne Mercury Hg Zinc Zn Iodine I Titanium Ti Oxygen O Aluminum Al Ca Calcium Sulfur S

Atomic Masses The mass comes from: the average mass of the isotopes protons and neutrons each weigh one atomic unit Remember Isotopes - different number of neutrons. Identified by name and mass number. Boron-10, Boron-11 Try It! 5 atoms of Boron, four are Boron-10, one is Boron-11. What is the average atomic mass? (10 + 10 + 10 + 10 + 11) / 5 = 10.2 u

What’s the diff? Atomic Weight: Is an AVERAGE – usually in decimal form. On the periodic table Mass number: The weight of that specific atom. Is a whole number. Often listed in the name (Boron-10, Carbon-14, Uranium-235) We will be more concerned with mass number because it is how we find the number of neutrons! (mass number-atomic number = neutron number)

Periodic Table Non-metals Noble Gas Metalloids Halogen Metals Transition Metals

Types of Elements Noble Gas: Chemically stable. Has outer valence level full. “Happy” AKA: Inert elements. Don’t bond with others. Halogens: Are non-metals. Bond VERY easily. Have 7 electrons in outer shell. Non-metals: Do not easily conduct electricity or heat. Metalloids: Have traits of both metals and non-metals. Metals: Good conductor of heat and electricity, shiny, ductile (pulled into a wire), and malleable (pounded into flat sheets) Transition metals: Metals that can have two different valence numbers. Is shown in the formula. Example: Fe (II)

Periodic Table Alkali metals Alkaline Earth metals Transition metals

Hindenburg (5 minutes)

Reasons for the crash (7 minutes)

Element symbols you need to know Gold Au Chlorine Cl Silver Ag Sodium Na Iron Fe Hydrogen H Lead Pb Helium He Copper Cu Carbon C

More element symbols Potassium K Neon Ne Mercury Hg Zinc Zn Iodine I Titanium Ti Oxygen O Aluminum Al Ca Calcium Sulfur S

Periodic Table Video Clip1

Periodic Table video clip2

Word Wizard vocabulary

Word wizard: Ionic Bond Your definition Important Points Bond that is formed by the “stealing” of electrons. One atom is now + and one is now -. This makes them attract to each other. Most are solid at room temp. Ionic Bond Examples Non-Examples Sodium Chloride: NaCl Sugar: C6H12O6 Water: H2O Diatomic molecules: Cl2, H2, N2 (gasses)

Word wizard: Covalent Bond Your definition Important Points Bond that is formed by the “sharing” of electrons. A stronger bond than ionic. Atoms can share more than one electron. Most are liquid or gas at room temp. Covalent Bond Examples Non-Examples Water: H2O Diatomic molecules: Cl2, H2, N2 (gasses) Sodium Chloride: NaCl Sugar: C6H12O6

Word wizard: Polar Molecule Your definition Important Points A molecule that has a positive end and a negative end Polar will mix with polar. Polar will not mix with non-polar Polar Molecule Examples Non-Examples Water: H2O Sugar: C6H12O6 Salt: NaCl Oil Grease Gasoline

Word wizard: Non-Polar Molecule Your definition Important Points Non-polar will mix with non-polar. Non-polar will not mix with polar A molecule that has an equal charge all over. Non-polar Molecule Examples Non-Examples Cooking Oil Grease Car oil (things that don’t mix with water) Water: H2O Sugar: C6H12O6 Salt: NaCl

Word wizard: Anion anion Your definition Important Points Anions have more electrons than protons. This makes them negative overall. An ion that has a negative charge; has extra electrons. anion Examples Non-Examples Chlorine Oxygen Nitrogen Non-metals Sodium Potassium Magnesium Metals

Word wizard: Cation Your definition Important Points Cations lose electrons. They have more protons than electrons and are positively charged. An ion that is positively charged; has less electrons Cation Examples Non-Examples Sodium Potassium Magnesium Metals Chlorine Oxygen Nitrogen Non-metals

Word wizard: Chemical Formula Your definition Important Points Large and small letters. Shows what elements are in a compound and how many of each. A shorthand way of writing compounds using their symbols. Chemical formula Examples Non-Examples Water Sugar Salt H2O C6H12O6 NaCl

Word wizard: Chemically Stable Your defintion Important Points Elements that have the outer electron shell full. Also called “Noble Gases” or “Inert Elements” Will not typically bond with other elements. Likes to be ALONE! Chemically Stable Examples Non-Examples Helium Krypton Neon Xenon Argon Radon Gold Carbon Sodium Nickel Potassium Oxygen

Valence Numbers Valence 1 2 3 4 5 6 7 8

Diatomic Molecules Covalent bond between identical atoms. Usually a gas Examples: H2 (hydrogen gas) O2(oxygen gas) N2(nitrogen gas) Nitrogen has 5 electrons in the outer shell. It wants 8. Two nitrogen atoms share three electrons. BONDED!

Making Compounds Let’s bond, shall we?

Valence Numbers Valence electrons: how many electrons are in the outer shell. Chemically stable: elements having their outer shell full. The noble gases are chemically stable without bonding. To fill the outer shell, elements can share or steal electrons (bond). To be “Happy” atoms typically want 8 electrons in the outer shell (ionic or covalent bonds)

Ionic bonding Stealing electrons This makes one negatively charged (it has an extra electron that it stole). The other is now positively charged (had an electron taken). Opposites attract! Ionic bonds are weaker than covalent. Compounds that are solids at room temperature are usually from ionic bonds.

Covalent Bonding From sharing electrons Covalent bonds are stronger than ionic Compounds that are liquids or gas at room temperature are typically covalent bonds. Diatomic: Some elements will covalently bond with themselves!

Common Household Compounds NaHC03 Baking Soda: Carbon Monoxide: CO SiO2 Sand: Ammonia: NH4 Carbon Dioxide: CO2 Salt: NaCl Bleach: NaClO Propane: C3H8 Vinegar: HCH3O2 Stomach Acid: Water: H2O HCl

Dihydrogen Monoxide The dangers, uses and potential threats posed by this chemical, Dihydrogen Monoxide, are widespread, and some feel, terrifying. Here is just a small taste of what Dihydrogen Monoxide (DHMO) is: Some call Dihydrogen Monoxide the "Invisible Killer" In it’s gaseous form, DHMO can cause severe burns Dihydrogen Monoxide is found in all cancerous tumors Dihydrogen monoxide was found at every recent school shooting Athletes use DIHYDROGEN MONOXIDE, or DHMO, to enhance performance Dihydrogen Monoxide has been found to cause failure in automotive breaks Dihydrogen Monoxide is a major component of acid rain Thousands die each year after inhaling dihydrogen monoxide Dihydrogen Monoxide can be deadly Visit DHMO.org to find out more

What’s in a name? Mono = one Di = two Tri = three Tetra = four Penta = five Examples: Carbon Monoxide CO Carbon Dioxide CO2 Dihydrogen Monoxide ?? H2O

P Dot Diagrams What you need to know to make a dot diagram: Chemical symbol valence number How to draw the dot diagram of an element: 1. Write the symbol 2. Find the valence number 3. Fill in dots two together (the S ones) one in other sides until you run out of room. P

More Dot Diagrams F Li Ge Mg Se Kr

Sr As He I’m still seeing dots! Why is this one right? Because Helium only has two electrons in the first place!

Oxidation numbers +1 +3 +/-4 -2 -1 +2 -3

Making Compounds H Cl = HCl Criss-Cross Method: List the Metal first, non-metal second. Write the oxidation number above the symbol. Criss-cross the numbers. (a 1 does not need to be written, drop the + or -) Final answer lists only the subscripts (numbers below the line) If they are the same number, they cancel out Example: Combine Hydrogen and Chlorine +1 -1 H Cl = HCl

Now try these... H O Mg N H2O Mg3N2 Hydrogen and Oxygen +1 -2 Magnesium and Nitrogen -3 +2 Mg N Mg3N2

Writing Equations (again??) Remember the “criss cross” method. Use the oxidation number Don’t write in 1’s or the charges Oxidation numbers of transition elements are given in a roman numeral. Put in “lowest terms” Example: Combine H and O +1 -2 H O H2O Example: Combine Fe (III) and O +3 -2 Fe O Fe2O3

Writing Equations: something new Monoatomic Ions: “normal” one element can get from the periodic table or roman numerals what you’ve been working with Example: H20 Example: Combine Potassium and Permanganate Polyatomic Ions: compounds that always work together. Always has more than one element Get the information off a chart Criss cross method still works. Keep these elements together! +1 -1 K MnO4 KMnO4

More Practice: Polyatomic Ions Combine: Iron (II) and Nitrate +2 -1 Fe NO3 Fe(NO3)2 Combine: Calcium and Carbonate -2 +2 Ca CO3 CaCO3

Word wizard Your definition Important Points Real example Analogy/memory hook Alloy The mixture can have new properties. (lower melt point, stronger, etc. Two or more metals melted down and mixed together. Not ALL metals are mixtures. (All = alloy) Alloys are like allies (mixed but not the same) Sterling silver, 14 karat gold, bronze, brass

Word wizard Your definition Basic equation Real example Analogy/memory hook Synthesis Reaction Reaction where substances are combined to make a new substance. A + B AB Like two people going out and becoming a “couple”. Dating is a “sin” 2Mg + O2 2MgO

Word wizard Your definition Basic equation Real example Analogy/memory hook Single replacement Reaction One ingredient “kicks out” the other. Leaders always stay leaders! A + BC AC + B D + BC BD + C Getting “dumped” for someone else. One ends up single Li + FeBr2 LiBr + Fe

Word wizard Your definition Basic equation Real example Analogy/memory hook Double replacement Reaction Elements will change partners in this type of reaction. Leaders are always leaders! AB + CD AD + CB Switching dates at the prom. Nobody gets left alone! AgNO3 + NaCl AgCl + NaNO3

Word wizard Your definition Basic equation Real example Analogy/memory hook Decomposition Reaction A substance is broken down into its “parts” in this reaction AB A + B A couple breaking up. Things “break down” when they decompose. 2H2O H2 + O2 elec

Word wizard Your definition Basic equation Real example Analogy/memory hook Combustion Reaction A reaction where two of the products are water and carbon dioxide A + B CO2 + H20 Combustion = fire Picture a fire with smoke (CO2) and water(H20) to put it out. HCl + Na2CO3 CO2 + NaCl + H2O

Word wizard Chemical reaction where heat is ABSORBED. Your definition Important Points Real example Analogy/memory hook Endothermic Reaction Chemical reaction where heat is ABSORBED. Heat being absorbed makes it feel COLD. Break and shake ice pack. (Heat is absorbed by ice pack, but it feels cold) Endo has a “d” in it. Cold has a “d” in it. Endothermic reactions FEEL cold.

Word wizard Chemical reaction where heat is released. Your definition Important Points Real example Analogy/memory hook Exothermic Reaction Chemical reaction where heat is released. This reaction will feel warm/hot. “Exo” = “exit” Heats EXITS an exothermic reaction. (it feels warm) “Hand warmers” BenGay, Thermocare hot wraps

You can’t play “God” Law of Conservation of Mass says that we can’t create or destroy mass! Example: the weight of a piece of paper will be the same as the weight of the ash, smoke, etc after you burn it!! In chemical reactions, you need to have the same amount of atoms before and after the reaction!

It’s a balancing act Ag + H2S Ag2S + H2 1 Ag 2 H 2 H 2 Not Balanced! Conservation of mass says we can’t create or destroy anything!! S 1 S 1

It’s a balancing act 2 Ag + H2S Ag2S + H2 Ag 1 2 Ag 2 H 2 H 2 S 1 S 1

Try balancing this: Balanced!! 2 Mg + O2 MgO 2 Coefficient: The “big” number that is put in front to show how many units you need to have. Mg 1 2 Mg 1 2 O 2 O 1 2 Balanced!! How to read it: 2 units of Magnesium added to oxygen gas yields 2 units of Magnesium Oxide