Binary, Polyatomic, Acids & Bases Chemical Composition Binary, Polyatomic, Acids & Bases

Electron Dot Diagram Electron Dot Diagrams are diagrams that are used to represent the structure of an atom, primarily focusing on the number of valence electrons. The nucleus and the full orbitals are represented with the chemical symbol of the element . The valence electrons are represented by the dots. When adding the dots: 1.There should not be more than 8 dots, because there cannot be more than 8 valence electrons. 2. There should not be more than 2 dots on a side. 3. There cannot be 2 dots on a side until every side has 1 dot. N

Ions Ion is an atom, or group of atoms, that is either positively or negatively charged as a result of the loss or gain of electrons. If an atom loses electrons, it loses negative charges, so it becomes a positively charged ion, or cation. (Ex. Al3+) If an atom gains electrons, it gains negative charges, so it becomes a negatively charged ion, or anion. (Ex. S2-) Some elements form two or more ions. Roman numerals are used to oxidation number of an ion. Cu1+ = Copper (I) ion Cu2+ = Copper (II) ion

Oxidations Number Oxidation number - indicates the number of electrons atom wants to either lose or gain to become stable. Atoms are stable when they have a completely filled outermost orbital (8 valence electrons, or 2 for Helium) Atoms with less than 4 electrons on the outer orbital will lose their valence electrons to become stable (except He) Atoms with more than 4 valence electrons will gain electrons to become stable (except noble gases, they already stable)

Determining Oxi Numbers To determine the oxidation number for an atom: 1. Find how many valence electrons the atom has. 2. Determine if it would be easier to lose or gain electrons to become stable. 3. The amount of electrons that the atom gains or loses to become stable is the oxidation number. 4. Determine the charge. If an atom gains electrons it will be (-) and if it loses electrons it will be (+).

Binary Compounds Binary compounds are compounds that consist of only two different elements. Compounds have specific and unique properties, which replace those of the elements that form them. Example: hydrogen and oxygen have very different properties from H2O (water). Only valence electrons participate in chemical bonding; inner electrons are in stable, fully occupied orbitals and do not participate in chemical bonds.

Polyatomic Ions - GOLD SHEET! Polyatomic ion- a group of covalently bonded atoms that acts like a single atom when combining with other atoms. Example: Ammonium - NH41+ Although the bonds within the polyatomic ion are covalent, it usually forms ionic bonds with other atoms. All polyatomic ions have a specific oxidation number, which does not change. A polyatomic ion acts as a unit, and the subscripts within the unit can NOT be changed at all.

Chemical Formula Chemical formula is combination of chemical symbols, which represents chemical shorthand for a compound. Chemical formula indicates what elements the compound contains and the ratio of the atoms of those elements in it. A subscript is a number written to the right and below of an element to show the number of atoms of the element present in the compound. If a symbol has no subscript, there is one atom of that element in a compound.

Ion Chips RULES (Pg. 6 & 12) Positive elements or Polys on the LEFT, roman numeral are the charge on the element, REMEMBER some have more than one. Negative elements or Polys on the RIGHT To complete the puzzle, all the pieces must make a perfect square/rectangle, there cannot any overhang. To write the formula: Write the positive element symbol first, and then the number of chips used as a subscript written down and to the left. Next write the negative element symbol, again with number of chips used as a subscript written down and to the left. Lets practice! Pg. 6 Iron (II) Chloride, Pg. 12 Iron (II) Nitrate

Writing Formulas Rules for writing chemical formulas for Ionic Compounds: 1. Write the symbol of the element or polyatomic ion with positive oxidation number. 2. Then write the symbol of the element or polyatomic ion with the negative oxidation number. 3.Crisscross oxidation numbers to become subscripts. Charge is NOT included. 4. Reduce subscripts so they are in the smallest ratio 5. Use oxidation numbers and subscripts to check that the total charge on the compound is neutral.

Criss - Cross Practice Na +1 O -2 Answer: Na2O Mg +2 S -2 Answer: MgS Make a formula between the following ions Na +1, O -2 Na +1 O -2 Answer: Na2O Mg +2, S - 2 Mg +2 S -2 Answer: MgS REDUCE SUBSCRIPTS 1 2 2 2

Writing Formulas w. Polys Special Rules Polyatomic ions act as one SUPER ion, you cannot change the subscripts The charge on the GOLD sheet for each poly is it’s oxidation number, that is the number you will use in the criss-cross method to create the chemical formula. Polys must have parenthesis when put into a formula if a subscript is added. Example 1: Mg(HCO3)2 - MUST HAVE PARENTHESIS Example 2: Na(HCO3) OR NaHCO3 - Does not have to, but can.

Criss - Cross w. polys Cu +2 SO4 -2 Answer: CuSO4 Or Cu(SO4) Make a formula between the following ions Zr +4, ClO3 -1 Zr +4 ClO3 -1 Answer: Zn(ClO3)4 Cu+2, SO4 -2 Cu +2 SO4 -2 Answer: CuSO4 Or Cu(SO4) REDUCE SUBSCRIPTS! 1 4 2 2

Naming Binary Compounds Ionic Bonds (Metal - NonMetal) You know you have a binary compound because there are only TWO capital letters First: Write the full name of the first element Second: Write the stem of the second element (GOLD SHEET) Third: Add the ending -ide Example: CaO Calcium 2. Oxi 3. - ide Answer: Calcium Oxide

Naming with multiple Oxi Numbers Metals with multiple oxidation numbers need to be labeled in the name, this is done with Roman Numerals (Ex. Fe, Mn, Ni, Pb, Hg, Cu) Naming rules are the same for Ionic Naming, but now we place a roman numeral between metal and nonmetal to represent the charge of the metal. 1- I, 2- II, 3 - III, 4 - IV, 5 - V, 6 - VI, 7 - VII, ect. You can find the roman numeral by: reverse criss- crossing to get the oxidation number, check the periodic table to make sure it works!

Naming with Roman Numerals Name the compound: Cu2O Reverse criss-cross - Cu+1O-2 Check the P.T, does this work? YES Write first element in full - Copper Roman Numeral to represent charge of the METAL - (I) Write second element with -ide ending - Oxide Answer: Copper (I) Oxide

Naming With Roman Numerals Name the compound: CuO 1) Reverse Crisscross - Cu+1O-1 2) Check your work Can O have a -1 charge?? What is O?? So what does Cu have to be?? Use the total charge chart to find the new oxidation number Answer: Copper (II) Oxide

Naming Covalent Bonds Covalent Bond: This is weak bond between two nonmetals, remember polar and non polar. Start with basic binary rules Add greek prefixes to indicate the number of each in the compound (Subscript) Exception-mono is never used on the first element.

Naming Covalent Name the compound: SO2 Write full first element with appropriate prefix, except mono - Sulfer Write second element with appropriate. Prefix, AND -ide ending - two (di) - oxygen (ox) -ide Put it all together Answer: Sulfur Dioxide

Naming Flow-Chart Ionic OR Covalent Bond? Does it start w/ a nonmetal? Naming Rules Ionic - Does the metal have more than one oxidation #? First element - full name If multiple oxidation # - ADD ROMAN NUMERAL Second - stem w/-ide Covalent - First Element - full name First element - greek prefix w/ full name (EXCEPT MONO) Second - greek prefix w/stem & -ide

Naming Polyatomic Compounds You know you have a polyatomic compound because you have MORE than 2 capital letters. Follow the same general rules as Ionic Compounds Check that the first element’s oxidation numbers Use the Gold-sheet to identify Polyatomic Ions Write the first elements full name, add roman numerals IF needed Write the name of polyatomic ion second, Do NOT change the ending

Acids, Bases & Salts Bases contain a metal and a hydroxide ion, OH-1 Identify bases by their components and then use basic binary rules to name them, don’t forget the roman numerals! Salts are ionic compounds that start with a metal and end with any ion except OH-1 Remember that ionic compounds contain ion and polyatomic ions, use your GOLD sheet to identify them.

Acids react with bases to form salts Acids react with bases to form salts. Acids can be identified as compounds that start with an H. You will NOT need to know naming rules for acids, just refer to your GOLD sheet.