CHEM 105N 1st Edition Lecture 17 Outline of Last Lecture I. Chemical BondsII. The Octet RuleIII. Ionic & Covalent BondsIV. Ionic & Covalent CompoundsOutline of Current Lecture I. Metals form Positive IonsII. Non-metals form Negative IonsIII. Ionic Charge by Group NumberIV. Ionic CompoundsV. Metals with Variable ChargeCurrent LectureI. Metals form Positive Ions:- Called cations- Working to achieve and octet by a loss of valence electrons to the nearest noble gas- Have fewer electrons than protonsII. Non-metals form Negative Ions:- Called anions- Working to achieve an octet by gaining electrons- (-3), (-2), or (-1) chargeIII. Ionic Charge by Group Number:- Work to achieve electron configuration of nearest noble gas by forming positive and negative ions- Positive Ions: Have a charge equal to its group numberEx. Group 1A (1) 1+Group 1A (2) 2+Group 3A (3) 3+- Negative Ions: Obtain their charge by subtracting 8 or 18 from its group numberEx.Group 6A (16) 6-8=2-These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.OR 16-18=2-IV. Ionic Compounds:- Consist of positive and negative ions- Have attractions called ionic bonds between positively and negatively charged ions- Have high melting and boiling points- Are solid at room temperatureChemical Formula for Ionic Compounds:- Lowest whole-number ratio of ions- Sum of positively and negatively charged ions is always ZERO- Total charges are balancedTotal positive charge = Total negative chargeEx.Compute: (Na^+) + (N^3-)1) Each take each other’s charge number (Balance the charges)2) 3(+1) + 1(3-) = 0Aka(Na+) (Na+) (Na+) + (N3-) = 03) Na3NEx.Compute: (Ba2+) + (Cl-)1) Balance the charges2) (Ba2+) + (Cl-) (Cl-)= 03) BaCl2- To name a cation with TWO elements:- Identify the cation and anion- Name the cation first followed by the name of the anionV. Metals with Variable Charge:- Most transition metals (3-12) and Group 4A (14) metals form 2 or more positive ions, except Zn2+, Ag +, and Cd2+, which form only one ion.- The names of transition metals with two or more positive ions (cations) use a Roman numeral after the name of the metal to identify the ion charge.- Name the anion by using the first syllable of the element name followed by “ide”Ex.- FeCl2 Iron(II)chloride- Fe2O3Iron (III)
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