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HSCE - Chemistry. C5.5B Predict the formula for binary compounds of main group elements. This is what Ms. Lolich wants you to know for the MME!!. Chemical Bonds. Chapter 6. Let’s Review. Chemical Formula Used to describe the molecules of an element as well as a compound. H 2
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HSCE - Chemistry • C5.5B Predict the formula for binary compounds of main group elements. This is what Ms. Lolich wants you to know for the MME!!
Chemical Bonds Chapter 6
Let’s Review Chemical Formula • Used to describe the molecules of an element as well as a compound. H2 2. The subscript 2 indicates that there are two atoms in a molecule of hydrogen.
Tips to keep in mind when naming and writing formulas: Always keep your Periodic Table handy – You should have it in front of you ALWAYS when you are naming and writing formulas. Remember that metals (except Hydrogen) are found to the left of the stairstep on the PT Nonmetals are found on the right side of the PT Transition Metals are found from Group 3 to the stairstep (except aluminum which is a regular metal)
The colors are different than your text but……still same info!
Binary Ionic Compounds • Compound made from only 2 elements. • Latin prefix bi means “two”. • Nonmetal will end with suffix – “ide”.
How do you name binary ionic compounds? Name the first ion 2. Name the second ion changing the suffix to “ide”. Let’s give it a try!!
Examples NaCl Name the metal ion Sodium Chloride Wasn’t that easy?!! CaO Name the nonmetal ion, changing the suffix to –ide. Oxide Calcium Al2S3 Aluminum Sulfide MgI2 Magnesium Iodide
Why do those last 2 have subscripts? Al2S3 Aluminum Sulfur -2 +3 Al S 3 2
How does criss cross work? Al2S3 Sulfur -2 Aluminum +3 Sulfur -2 Aluminum +3 Sulfur -2 Aluminum +6 Sulfur -6 Now they both have a neutral charge as a molecule
Transition metals • Many can have more than one type of ion. • The name of the ion contains a Roman numeral to indicate the charge on the ion. Ie: copper(II) Cu2+
Let’s look at the transition metals and using roman numerals? Notice – metal and nonmetal. FeO Name the first ion. Since the first ion is a transition element, you must use a Roman Numeral to represent the charge. How do you know the charge? Deductive reasoning by looking at Oxygen Oxygen has a -2 charge (group 16) Therefore ….. Iron must have a +2 charge since there is one iron and one oxygen. Iron gets a Roman Numeral II. Isn’t this easy and FUN!!! (II) Oxide Iron
Cu2S Name the first ion. Since it is a transition metal, you must use a Roman Numeral. How do you find the charge? Look at sulfur Sulfur has a -2 charge (group 6A) There are two coppers. Therefore each copper must have a +1 charge for all ions to be neutral +1 and +1 = +2 Copper (I) Sulfide
Another Example: MnO2 Name the first ion. Since it is a transition metal, you must use a Roman Numeral. How do you determine the Roman Numeral? Let’s look at oxygen. Oxygen (group 6) has a -2 charge. There are 2 oxygens so the charge is….? Therefore, Mn must have a +4 charge for this compound to be neutral. Manganese (IV) oxide
How do we balance a polyatomic ion? Calcium Carbonate Name the first ion Determine the charge of the ion. Determine the charge of polyatomic ion. Carbonate has a -2 charge (use table in text) +2 -2 Calcium Carbonate Since they both are a net zero charge they are balanced
How do we balance a polyatomic ion? Magnesium Phosphate Name the first ion Determine the charge of the ion. Determine the charge of polyatomic ion. Phosphate has a -3 charge (use table in text) -3 Magnesium +2 Phosphate Both DO NOT net zero so they are unbalanced Mg PO4 ( ) 3 2
How does criss cross work? Mg3(PO4)2 Magnesium +2 Magnesium +2 Phosphate -3 Magnesium +2 Phosphate -3 Magnesium +6 Phosphate -6 Now they both have a neutral charge as a molecule
Review How is the Roman numeral in the name related to the charge on the ion? • It is equal to 1/100 the charge on the ion. • It is equal to one half the charge on the ion. • It is equal to the charge on the ion. • It is equal to the group number.
Answer How is the Roman numeral in the name related to the charge on the ion? • It is equal to 1/100 the charge on the ion. • It is equal to one half the charge on the ion. • It is equal to the charge on the ion. • It is equal to the group number.
Which element is found in all the anions whose names end in -ate? • carbon • oxygen • nitrate • sulfate
Answer Which element is found in all the anions whose names end in -ate? • carbon • oxygen • nitrate • sulfate