Chemical Bonding and Ionic Compounds: Understanding Atomic Structure

1. Review How many atoms of each elements are in the following compounds? H2O: Hydrogen = ___ Oxygen = ___ C6H12O6: Carbon = ___ Hydrogen = ___ Oxygen = ___ HCl: Hydrogen = ___ Chlorine = ____

2. Review cont… • The magic stable number of electrons on the outer shell is _____! This is the whole point of bonding, to have a stable outer shell of ___ valence electrons!

3. Bonding

4. Types of Chemical Bonds • Ionic Bonds: the transfer of electrons from one atom to another • One atom loses electrons (the metal) and the other gains (the nonmetal) • Occurs between a metal and a nonmetal • There is an equal exchange/transfer of electrons

5. Types of Chemical Bonds • Covalent Bonds: the sharing of electrons between atoms. • Occurs between two nonmetals. • Example: C + O (two nonmetals) form a covalent bond Octets are obtained by sharing electrons, instead of gaining or losing electrons

6. Practice Identifying Types of Bonds • Write I for ionic bond, C for covalent bond, or N for no bond 1. Na + Cl 6. O + C 2. K + Br 7. Ga + S 3. N + O 8. Ar + F 4. Ne + O 9. Cs + P 5. Mg + O 10. C + Br

7. More about Ionic Bonding

8. Oxidation Number • The charge given to the atom based on the number of electrons it will gain or lose in an ionic bond. • Atoms that lose electrons will have a positive charge. Those atoms that tend to gain electrons will have a negative charge . • Most of the time, nonmetals will have a negative oxidation number

9. Ions • As atoms gain/lose electrons, the two atoms become stable. • Atoms that have a charge are called ions. The ionic bond occurs because the positively charged ion is attracted to the negatively charged ion (opposites attract)

10. What do the following ions mean? • Example: O 2-= Oxygen gained 2 electrons 1.Sn4+ = 2. Hg 2+= 3. Li+= 4. P3- = 5. S2-= 6. N3-=

11. Forming Ionic BondsExample • Sodium (Na) lost one electron. Sodium is a metal • Chlorine (Cl) is a non-metal. It gained one electron. • Metals typically lose electrons, giving them a positive charge • Non-metals typically gain electrons, giving them a negative charge.

12. Naming Ionic Compounds

13. Chemical reactions occur when atoms gain, lose, or share electrons. Metals Nonmetals gain / accept Nonmetals _____________ electrons. This gives them a ____ charge. _ lose / donate Metals ________________ electrons. This gives them a ____ charge. +

14. Remember that the charge of an ion can be determined by its place on the Periodic Table. +1 0 +4 or -4 +2 -2 -1 +3 -3

15. For each elements on your notes, predict the charge of its most common ion using the periodic table. 0 +2 -3 +2 -1 +2 -1 -2 +1 +1

16. Rules for Naming Ions When metals lose electrons they become ions, but their name does not change. Na Na+ + e- electron sodium sodium Mg Mg+2 + 2e- 2 electrons magnesium magnesium

17. Rules for Naming Ions When nonmetals gain electrons they become ions, and their name does change. F + e- F- fluoride fluorine electron S + 2e- S-2 sulfur 2 electrons sulfide

18. Rules for Naming Ions 1. The names of metals do not change. 2. Nonmetals come second and add –ide at the end: root of element name + -ide = name of ion Examples: The name of chlorine’s ion: chlor- + -ide = chloride The name of nitrogen’s ion: nitr- + -ide = nitride

19. Examples of naming ions: The name of calcium’s ion: calcium (The names of metals don’t change!) The name of oxygen’s ion: ox- + -ide = oxide The name of aluminum’s ion: aluminum (The names of metals don’t change!)

20. Write the name of each of the ions on your notes. sulfide lithium nitride bromide potassium chloride oxide

21. Steps for Naming Ionic Compounds CaBr2 calcium bromide Step 1: Ladies first! Write the name of the metal ion. Step 2: Guys second! Write the name of the nonmetal ion. Don’t forget to add –ide! Step 3: YOU ARE DONE! It is that easy.

22. 1. NaF 2. MgO sodium fluoride magnesium oxide 3. SrCl2 4. Li2S strontium chloride lithium sulfide 5. CaO 6. KI calcium oxide potassium iodide

23. Name the ionic compounds that are found on your notes. calcium chloride potassium sulfide barium oxide cesium chloride sodium bromide aluminum phosphide

24. Steps for Writing Ionic Formulas magnesium iodide Mg +2 I -1 MgI2 Step 1: Write the symbol of the metal ion. Step 2: Write the symbol of the nonmetal ion. Step 3: Determine the oxidation number of each using the periodic table. Step 4: Criss cross the oxidation numbers and write as subscripts.

25. Steps for Naming Ionic Compounds If the oxidation numbers are the same, just write the symbols: Na+1 + Cl-1 = NaCl Remember, if the number is 1, it is understood and we don’t write it: Mg+2 + I-1 = MgI2

26. Write the formula of each of the ionic compounds named on your notes. KI SnCl4 BaSO4 NaCl SrS CuCO3 AlBr3 Li3N

27. STOP

28. Naming Binary Covalent Compounds

29. shared electrons Nonmetals Chemical reactions occur when atoms gain, lose, or share electrons. Sharing electrons creates a covalent bond Nonmetals can _______ electrons to form a covalent bond. This creates a ___________. share molecule

30. Determining if a compound is ionic or covalent is easy. What elements do covalent compounds contain? Covalent compounds contain only nonmetals. What elements do ionic compounds contain? Ionic compounds contain a metal and a nonmetal.

31. Decide whether the compounds on your notes are ionic or covalent. C C I I C I

32. Important Facts: Because hydrogen only has 1 proton and 1 electron, it behaves differently than any other element on the periodic table of elements. Hydrogen can donate its 1 electron. H+ H2 Hydrogen can share electrons. Hydrogen can gain 1 electron. H- This means that hydrogen can act as either a metal or a nonmetal!

33. There are 7 elements that exist in nature as diatomic molecules. What elements exist as diatomic molecules? H2, N2, O2, F2, Cl2, Br2, I2

34. There are millions of covalent compounds. These can be classified into many different types of compounds. Each type of compound has a different set of rules for naming. You will be learning about the easiest type of covalent compound to name: Binary Covalent Compounds Binary means 2. What does binary mean? Binary covalent compounds are between 2 different nonmetals.

35. Nonmetals can share electrons in many different ways. This means that two nonmetals can create multiple compounds together. carbon and oxygen phosphorous and chlorine CO CO2 PCl3 PCl5 nitrogen and oxygen N2O4 N2O3 Each of these contains a different ratio of elements. Because of this, we have to make sure that the name of the compound explains the correct ratio.

36. To show the correct ratio of elements, we use prefixes.

37. Steps for Naming Binary Covalent Compounds N2O4 dinitrogen tetroxide nitrogen oxide Step 1: Write the name of the first nonmetal. Step 2: Write the name of the second nonmetal changing its ending to -ide. Step 3: Add prefixes to specify how many of each element are present.

38. Rules for Using Prefixes Rule 1: Prefixes are only for BINARY COVALENT compounds. Rule 2: The prefix mono- is never used on the first element of a binary covalent compound. Without a prefix it is assumed that there is only 1. Example:CO2 is carbon dioxide, and not monocarbon dioxide. Rule 3: Remove the -o or -a from a prefix before adding it to oxide. Example:CO is carbon monoxide, and not carbon monooxide.

39. How would you write each of the prefixes in front of oxide? Remember: Remove the -o or -a from a prefix before adding it to oxide. Leave -i alone. mono- ____________ di- ____________ tri- ____________ tetra- ____________ penta- ____________ hexa- ____________ hepta- ____________ octa- ____________ nona- ____________ deca- ____________ monoxide dioxide tetroxide trioxide pentoxide hexoxide octoxide heptoxide decoxide nonoxide

40. Name the binary covalent compounds that are found on your notes. carbon dioxide carbon disulfide phosphorous tribromide phosphorous pentabromide diphosphorouspentasulfide dinitrogenmonosulfide silicon disulfide nitrogen tribromide dinitrogen tetrachloride

41. Because of the prefixes, it is very easy to go from the name of a binary covalent compound to its formula. dinitrogen tetrafluoride N2 F4 Step 1: Write the symbol of the first nonmetal and the subscript that matches the prefix. Step 2: Write the symbol of the second nonmetal and the subscript that matches the prefix.

42. Write the formulas of the binary covalent compounds in your notes. CCl4 IF7 PCl5 N2O4 N2O PCl3 CS CO BH3 ICl S2Br6 S4N4 H2O SiS2 PI3 ClF5 NO2 NCl3

43. STOP

44. Naming Ionic and Covalent Compounds Review

45. Chemical reactions occur when atoms gain, lose, or share electrons. This is what creates compounds! gain / accept Nonmetals _____________ electrons. This gives them a ____ charge. Negative ions are called ___________. _ anions Metals ________________ electrons. This gives them a ____ charge. Positive ions are called ___________. lose / donate + cations

46. What elements do ionic compounds contain? Ionic compounds contain a metal and a nonmetal. Nonmetals Metals

47. Steps for Naming Ionic Compounds MgCl2 magnesium chloride Step 1: Write the name of the metal ion. Step 2: Write the name of the nonmetal ion. Remember that we change the name of nonmetal ions to –ide. YOU ARE DONE! It is that easy.

48. shared electrons Nonmetals Chemical reactions occur when atoms gain, lose, or share electrons. Sharing electrons creates a covalent bond Nonmetals can _______ electrons to form a covalent bond. This creates a ___________. share molecule

49. What elements do covalent compounds contain? Covalent compounds contain only nonmetals. Nonmetals

50. Steps for Naming Covalent Compounds P2S4 phosphorous tetrasulfide sulfide diphosphorous Step 1: Write the name of the first nonmetal. Step 2: Write the name of the second nonmetal changing its ending to -ide. Step 3: Add prefixes to specify how many of each element are present.