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Chemical Bonding

Explore the types of chemical bonding - ionic, covalent, and metallic bonds - and learn how they determine the properties of matter. Discover the observations and essential questions surrounding chemical bonding. Watch demonstrations and videos to better understand energy changes in bonding and the formation of different types of bonds.

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Chemical Bonding

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  1. Chemical Bonding Comparison of Properties Ionic Compounds Covalent Compounds Metals

  2. More electronegative 1+ 2+ 3+ 3- 2- 1- Non-Metal Metal Less electronegative

  3. Observations • Look at the 10 vials, what elements are in them? • Some vials will contain multiple elements, name all of the elements (the symbols will do) • Write if they are metals or non-metals • Leave the last column blank.

  4. Essential Questions • Why/How do atoms combine with one another to form the vast array of chemical substances that exist? • What is ionic, covalent and metallic bonding and how do the types of bonding determine properties of matter? 

  5. Macroscopic properties of matter vary greatly due to the type of bonding Properties of Matter

  6. What is a chemical bond? • An attractive force that holds two atoms together • This attractive force can form by • The attraction of positive ion to a negative ion or • The attraction of the positive nucleus of one atom and the negative electrons of another atom

  7. Bond • the interaction between two or more atoms that allows them to form a substance different from the independent atoms. • involves the outer (valence) electrons of the atoms. • These electrons are • transferred from one atom to another or shared between them.

  8. Chemical Bond Energy Considerations • A chemical bond forms when it is energetically favorable • when the energy of the bonded atoms is less than the energies of the separated atoms. • Al + I2 https://www.youtube.com/watch?v=XBPqSuIN-3E

  9. Bonding • Chemical compounds are formed by the joining of two or more atoms. • A stable compound occurs when the total energy of the combination has lower energy than the separated atoms. • The bound state implies a net attractive force between the atoms ... a chemical bond.

  10. Energy Changes in Bonding • When bonds are formed, energy is released. • Demonstrations: • Formation of an Ionic Compound: Mg + O2 https://www.youtube.com/watch?v=dH6p5YwEME4 • Formation of a Molecular Compound: S +O2 • https://www.youtube.com/watch?v=SJUX6sJMCG0

  11. Breaking Bonds • In order to break bonds energy must be added, usually in the form of heat, light, or electricity. • Demonstration: Electrolysis of water • Demo: Decomposition of Nitrogen Triiodide • http://www.youtube.com/watch?v=z5vsQ8sPgX4

  12. Three Types of Bonding Ionic Metallic Covalent

  13. Types of bonds • Metallic- Chemical bonds between metal atoms • Covalent- Chemical bonds between non-metal atoms • Ionic- Chemical bonds between metal and nonmetal atoms • Fill out the columns on the front page and label them metallic, covalent or ionic.

  14. Chemical Bonds In chemical bonds, atoms • can either transfer or • share their valence electrons.

  15. When atoms transfer electronsIonic Bonds When one or more atoms lose electrons and other atoms gain them in order to produce a noble gas electron configuration, the bond is called an ionic bond.

  16. Ionic Bonding • Metallic atoms tend to lose electrons • When they do so, they become positively charged ions which are called cations. • Nonmetallic atoms tend to gain electrons to become negatively charged ions which are called anions.

  17. Ionic Bonding • These oppositely charged cations and anions are attracted to one another because of their opposite charges. • That attraction is called an ionic bond. We often refer to the charge on the ion as the oxidation state of that element.

  18. Na has one valence electron. • It loses it to Chlorine. • Na now has a filled valence shell. (an octet) • Becomes positive one in charge • Chlorine has seven valence electrons. • It gains one electron from Na. • Chlorine now has filled octet. • Chlorine has a negative one charge. (Chloride ion) • Na+1 attracts Cl-1 and forms the ionic bond. Positive Ion (Cation) Formation Negative Ion (Anion) Formation

  19. Metals Nonmetals

  20. Ionic Bonds • Part 1 • http://www.youtube.com/watch?v=Qf07-8Jhhpc • Part 2 • http://www.youtube.com/watch?v=5EwmedLuRmw • Part 3 • http://www.youtube.com/watch?v=RkZNYuSho0M

  21. Ion Formation • All of the elements in Group I (Column I) have one electron in their outermost energy level. • All of these elements can lose that one valence electron. • These atoms become cations with a positive one charge.

  22. Elements in Group II (Column II) have two electrons in their outermost energy level. • So, when these elements lose electrons, they lose two electrons and take on a positive two charge.

  23. The transition metals and the metals to the right of them generally form more than one ion. • We call these elements multivalent. The charges on their ions are not always predictable, although some patterns do exist. • A few of the transition elements form only one ion or oxidation state. For example zinc ion, silver ion and scandium ion. • Zn2+ zinc ion • Ag+ silver ion • Sc3+ scandium ion

  24. Anions • Nonmetals tend to gain electrons. • The halogens - fluorine, chlorine, bromine, and iodine - have a strong attraction for electrons. • Their outermost energy levels are almost full. There is only room for one more electron in the outer energy levels for each of those atoms. Consequently, the elements fluorine, chlorine, bromine, and iodine will gain one electron, and become anions with a negative one charge. • Oxygen, sulfur, and the other elements in that family will gain two electrons. • In the next group over, nitrogen, phosphorus and arsenic can take on three electrons.

  25. +1 +2 +3 -3 -2 -1

  26. Ionic Nomenclature • Naming Ionic Compounds • Video of the Process • http://www.youtube.com/watch?v=URc75hoKGLY

  27. Ionic Compounds • Made of cations and anions • Metals and nonmetals • The electrons lost by the cation are gained by the anion • The cation and anions surround each other • Smallest ratio of ions in an ionic compound is a FORMULA UNIT.

  28. Cations • Positive ions • Formed by losing electrons • More protons than electrons • usually Metals K+1 Has lost one electron Ca+2 Has lost two electrons

  29. Anion • A negative ion • Has gained electrons • Non metals • Charge is written as a super script on the right. F-1 Has gained one electron O-2 Has gained two electrons

  30. Formula Unit • The smallest whole number ratio of atoms in an ionic compound is a formula unit. • Ions surround each other so you can’t say which is hooked to which

  31. Naming Ions • We will use the systematic way • Cation- if the charge is always the same just write the name of the metal • Transition metals can have more than one type of charge • Indicate the charge with a Roman numeral in parentheses

  32. Name these • Na+1 • Ca+2 • Al+3 • Li+1 sodium calcium aluminum lithium

  33. Write Formulas for these • Potassium ion • Magnesium ion • Copper (II) ion • Chromium (VI) ion • Barium ion • Mercury (II) ion K+ Mg+2 Cu+2 Cr+6 Ba+2 Hg+2

  34. Naming Anions • Change the element ending to – ide • F-1 Fluorine

  35. Name these • Cl-1 • N-3 • Br-1 • O-2 • S-2 Chloride Nitride Bromide Oxide Sulfide

  36. Write these • Sulfide ion • iodide ion • phosphide ion • Chlirde ion S-2 I-1 P-3 Cl-

  37. Homework (due Friday Feb 2) • Name these ions • I- • S2- • Ca2+ • Na1+ • N3-

  38. Polyatomic ions • Groups of atoms that stay together and have a charge • You must memorize these or use an ion sheet… common examples • Acetate C2H3O2-1 • Nitrate NO3-1 • Nitrite NO2-1 • Hydroxide OH-1 • Permanganate MnO4-1 • Cyanide CN-1

  39. More Polyatomic ions • Sulfate SO4-2 • Sulfite SO3-2 • Carbonate CO3-2 • Chromate CrO4-2 • Dichromate Cr2O7-2 • Phosphate PO4-3 • Phosphite PO3-3 • Ammonium NH4+1

  40. Practice with Ions • Use the practice worksheet to determine the ions formed. • Learn to use your periodic table and pink sheet to determine charges (oxidation state.)

  41. Binary Ionic Compounds • Binary Compounds • 2 elements. • a cation and an anion. • To write the names just name the two ions. • Easy with Representative elements • Groups 1, 2, 13 • NaCl = Na+ Cl- = sodium chloride • MgBr2 = Mg+2 Br- = magnesium bromide

  42. Naming Binary Ionic Compoundswith Variably Charged Cations • The problem comes with the transition metals (Groups 3-12) since their charge can vary • Need to figure out their charges • The compound must be neutral • same number of + and – charges. • Use the anion to determine the charge on the positive ion • Charge of the cation is a Roman numeral in the name

  43. Example • Write the name of CuO • Need the charge of Cu • O is -2 • copper must be +2 • Copper (II) chloride

  44. Example • Name CoCl3 • Cl is -1 and there are three of them = -3 • Co must be +3 Cobalt (III) chloride

  45. Another Example • Write the name of Cu2S. • Since S is -2, the Cu2 must be +2, so each one is +1. • copper (I) sulfide

  46. Last Example • Fe2O3 • Each O is -2 3 x -2 = -6 • 3 Fe must = +6, so each is +2. • iron (III) oxide

  47. Naming Binary Ionic Compounds • Write the names of the following • KCl • Na3N • CrN • Sc3P2 • PbO • PbO2 • Na2Se

  48. Ternary Ionic Compounds • Will have polyatomic ions • At least three elements • Name the ions • NaNO3 • CaSO4 • CuSO3 • (NH4)2O

  49. Ternary Ionic Compounds • LiCN • Fe(OH)3 • (NH4)2CO3 • NiPO4

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