Why does an element want to bond?

Why does an element want to bond?

State 3 differences between ionic vs. covalent compounds

What is a chemical formula? It indicates the relative number of atoms of each kind in an ionic compound. Ex Al 2 O 3 has 2 atoms of Al and 3 atoms of O. It indicates the number of atoms of each element contained in a single molecule of a molecular compound. Ex. C 8 H 18 has 8 atoms of carbon and 18 atoms of H in a molecule of octane.

There are different rules for naming and writing formulas for ionic and covalent compounds. The compound is ionic if it is composed of a cation and an anion, or a metal and a nonmetal. The elements will be located on opposite sides of the periodic table. They have a high electronegativity difference. The compound is covalent (or molecular) if both elements are nonmetals.

Binary because composed of only 2 elements. Ionic because composed of a metal and a nonmetal. Example aluminum oxide.

1). Write the symbol and charge for the cation. 2). Write the symbol and charge for the anion. 3). Criss cross the oxidation numbers and drop the charges. The oxidation number will become the subscript for the other element. 4). Reduce the subscripts if possible. If they are the same, they cancel completely. 5). If the subscript is 1, do not write anything.

Write the formula for calcium iodide. Write symbols and charges. Ca +2 I -1 Criss-cross oxidation numbers, drop charges. Ca 1 I 2 Cancel and take away ones. Answer: CaI 2

Question: Write the formula for Magnesium Oxide. 1) Write the symbol and charge. Mg +2 O -2 2) Criss cross oxidation number and drop charges. Mg 2 O 2 3). Cancel and don t write 1 s. Answer: MgO Complete page 4 and the bottom of page 5 of formula writing packet.

If a compound consists of a metal and a nonmetal, we use the name of the first element (always the cation) followed by the second element (always the anion). For the anion only, drop the last syllable and add ide. Subscripts are not included in the name. Examples: CaO: calcium oxide LiCl: lithium chloride K 2 S: potassium sulfide

P. 223 sample problem A P. 223 practice #1 a-e, and #2 a-f Complete packet page 1 and 8.

Some elements, such as iron, form 2 or more cations with different charges. To distinguish the ions formed by such elements, scientists use the Stock system of nomenclature. This system uses a Roman numeral to indicate the ion s charge. The numeral is enclosed in parentheses and placed immediately after the metal name. Fe +2 is iron (II) and Fe +3 is iron (III) Names of metals that commonly form only one cation, do not include a Roman numeral.

CuCl 2 Determine the charges of each element, by writing ions side by side. Backwards criss-cross to determine charge of cation. Name by writing name of cation, roman numeral, name of anion with ide instead of last syllable. Cu Cl -1 Cu +2 Cl -1 Copper(II) chloride

Example: Write the formula of lead(iv) oxide. Write symbols with charge. Pb +4 and O -2 Criss cross and drop signs. Pb 2 O 4 Reduce and remove 1 s. PbO 2

Page 225 #1(a-f) and #2 (a-d) Complete packet page 3 and 5(top)

A covalently bonded group of atoms that has a positive or negative charge and act as a unit is a polyatomic ion. The prefix poly means many. Most simple polyatomic ions are anions. Ammonium (NH 4 ) is the only polyatomic cation. Sometimes there are parentheses in the formula, so you can tell its polyatomic.

If it contains a polyatomic ion, it is ionic, so it follows the rules for naming ionic compounds. If anion is polyatomic, do not change the ending to ide. Keep it the same as is listed on the chart. Name cation then name anion. If the cation is polyatomic and the anion is binary, name is just like before. The ide ending means the anion is not polyatomic.

Al 2 (SO 4 ) 3 Al +3 and SO 4-2 Aluminum sulfate Fe(OH) 2 Fe +2 and OH -1 Iron(II)hydroxide

1. Write the symbols for the monatomic and polyatomic ions in the compound. 2. Look up the oxidation numbers of the ions involved. If a single atom, use the periodic table. If roman numeral (variable oxidation number) or polyatomic, use the chart. 3. Criss cross the oxidation numbers, and drop the charges. 4. Put polyatomic ions in parentheses if they have a subscript. 5. Reduce (simplify) and erase ones. 6. DO NOT ADD< SUBTRACT, MULTIPLY, OR DIVIDE. Just criss cross and reduce if necessary!

Write the formula for Lead (II) hydroxide. 1. Write the symbol and oxidation number. Pb +2 OH -1 2. Criss cross charges and drop signs. Pb 1 OH 2 3. Use parentheses if needed. Pb 1 (OH) 2 4. Reduce and drop 1 s. Pb(OH) 2

Write the formula for ammonium sulfate. 1. Write the symbol and oxidation number. NH 4 +1 SO 4-2 2. Criss cross charges and drop signs. Use parentheses if needed. (NH 4 ) 2 (SO 4 ) 1 3. Reduce and drop 1 s. (NH 4 ) 2 (SO 4 )

Pringles ammonium phosphate Bisquick sodium hydrogen carbonate (sodium bicarbonate) Mac n cheese-calcium phosphate Bacon bits sodium nitrite

Magnesium hydroxide Ferric sulfate Calcium nitride Aluminum phosphide

Check answers using the key provided online. www.gavirtuallearning.org Resources Shared Click here Science left side Chemistry left side Chemical formulas & equations View Tab 4 Gray box on right side of page--- Binary & Ternary Compound key

Lithium oxide Silver hydroxide Magnesium sulfate Ammonium carbonate Calcium phosphide Tin (IV) or Stannic oxide Tin (IV) or Stannic iodate Cuprous or Copper (I) nitrate Manganese sulfide Potassium permanganate Aluminum sulfate Omit Mercury (II) or mercuric perchlorate Iron (III) or ferric cyanide

Naming: 2, 3, 4, 7,10 only Add: WRITE FORMULA 1. plumbic oxide 2. stannous carbonate 3. aluminum nitride 4. strontium phosphate 5. gallium hydroxide

2. lithium chloride 3. magnesium sulfide 4. stannic or Tin (IV) chloride 7. aluminum oxide 10. plumbic or Lead (IV) oxide ***reduced** 1. 2. 3. 4. 5.

Molecular/covalent compounds are made of 2 nonmetals. Generally, the most metallic element is written first. These elements are farther to the left in the periodic table. If both elements are in the same group, the more metallic element is closer to the bottom of the group. The name of the second element is changed to -ide. Because molecular formulas can combine in many combinations, prefixes are used to indicate the subscript. Do not criss cross and do not use oxidation numbers. Don t use mono on first element.

1- mono 2- di 3- tri 4- tetra 5- penta 6- hexa 7- hepta 8- octa 9- nona 10- deca

P 2 O 5 Prefix of 1 st element, name of 1 st element Prefix of 2 nd element, name of 2 nd element, change ending to ide. Diphosphorus pentaoxide CO Carbon monoxide (Don t write mono on first element.)

Write the symbols for the elements in the order that they appear in the name. The prefixes indicate the number of atoms of each element in the molecule. The prefixes appear as subscripts in the formulas. If there is no prefix, there is only one atom. (1 st element only) Remember, do not criss cross. Example tetraphosphorus dichloride P 4 Cl 2

Write the formula: 1. Dibromine heptasulfide 2. Selenium tetrafluoride 3. Carbon monoxide 4. Nitrogen trichloride Name: 1. NO 2. P 2 O 5 3. P Cl 3 4. C I 4

Br 2 S 7 Se F 4 C O N Cl 3 Nitrogen monoxide Diphosphorus pentoxide Phosphorus trichloride Carbon tetraiodide

Magnesium dichromate (ionic) Antimony pentachloride (covalent) Tin (IV) or stannic sulfide (ionic) reduced form Dinitrogen monoxide (covalent) Aluminum acetate (ionic) Zinc nitrite (ionic)

Write formulas for: 1. Zinc nitride 2. Boron trifluoride 3. Calcium hydroxide 4. Plumbic selenide 5. aluminum dichromate Name these:

***1 ST PUT I (ionic) OR C (covalent) BESIDE THE QUESTION FRONT LEFT COLUMN: 1 20, 25, 26 FRONT RIGHT COLUMN: 1 18, 23, 25, 26

HCl This is binary, H and Cl. Follow rule #1. Hydrochloric acid H 2 SO 4 - This is polyatomic. Hydrogen and sulfate (SO 4 ) -2. Must find polyatomic anion and name. Ending is -ate so change to -ic. Sulfuric acid (notice no hydro, hydro is only for binary acids). HNO 2 - Polyatomic, H and nitrite. -ite becomes ous. Nitrous acid.

What do I know about acids? What do I want to know about acids? What have I learned today about acids?

What element do ALL acids start with? If the acid is binary use prefix AND the suffix. If the acid is ternary, do not use a prefix but change the polyatomic anion ATE= ITE=

HF HNO 3 H 2 SO 3 HBr HC 2 H 3 O 2 HClO H 3 PO 4

Hydrofluoric acid Nitric acid Sulfurous (sulfous) acid Hydrobromic acid Acetic acid Hypochlorous acid Phosphoric (phosphic) acid

All will end in the word acid. You must swap and drop charge like you did for ionic. Example: chromic acid Example: hydroiodic acid

Benzoic acid Hydrochloric acid Cyanic acid Chlorous acid Carbonic acid Hydrobromic acid Arsenous acid

H 2 C 7 H 6 O 2 H Cl H CNO H ClO 2 H 2 CO 3 H Br H 3 AsO 3

WRITE FORMULA: NAME: 1.hydrofluoric acid 1. H 2 SO 3 2.arsenous acid 2. H Br 3. acetic acid 3.HCl 4. hydroiodic acid 4. H 2 CO 3 5. phosphoric acid 5. H IO 4

Silicon tetrabromide Diphosphorus pentasulfide