1. Combining Elements How Chemical Compounds Are Made

2. Combining Elements Elements can exist on their own but most matter consists of two or more elements combined together How do they combine??

3. Metals and Non-metals Metals have a tendency to lose electrons and form positive (+) ions. Non-metals tend to gain electrons and form negative (-) ions Positive and negative charges attract When a positive ion and a negative ion bind together they form an ionic bond

4. Example (Sodium and Fluorine) An atom of Sodium has a single electron in its outer orbittal. This makes it unstable An atom of fluorine has seven electrons in its outer orbital. It needs one more to be stable.

5. Metal and Non-Metal So they make a deal! The sodium gives an electron to fluorine Now they’re both happy

6. The only thing is: – They’re not atoms any more They’re IONS An ion is like an atom but it has a charge Now REMEMBER – Opposites attract!

7. Ionic Compounds So sodium and fluorine are attracted to each other and form an inseparable bond And they call themselves Sodium Fluoride!! ( or NaF) Sodium Fluoride is an Ionic Compound

8. Ionic Compounds Here’s another example: Let’s take Calcium and Chlorine Calcium needs to get rid of two electrons to be stable but Chlorine only needs one. SO WHAT CAN THEY DO?

9. Building Ionic Compounds What if Chlorine found a friend? Another chlorine atom!

10. Making Ionic Compounds Now Calcium can give one electron to each of them! Now everyone’s happy!

11. Making Ionic Compounds This compound is called Calcium Chloride Or CaCl 2 Because there is one calcium ion and two chlorine atoms

12. Making Ionic Compounds Making ionic compounds is easy if you follow a few rules 1.Write down the name (or symbol) of each element starting with the metal e.g. Potassium (K) Sulfur (S) 2. Beside each one, write down the number of electrons that the element needs (or has to give away) to be stable K (1) S (2) 3. Now criss cross the numbers K (1) S (2)

13. Making Ionic Compounds This gives us K 2 S or Potassium Sulfide Try these MetalNon-metalMetal Symbol & Electrons to lose Non-metal Element and Electrons to gain Final Formula (Criss cross) MagnesiumNitrogenMg (2)N (3)Mg 3 N 2 LithiumChlorine CalciumCarbon AluminumSilicon

14. One last thing – If you can divide both numbers by a highest common factor: DO IT!! – Example: Calcium Oxide Ca 2 O 4 2 and 4 are both divisible by 2 so Ca 2 O 4 becomes CaO 2

15. Naming Binary Ionic Compounds A binary ionic compound is an ionic compound with two elements. They’re very easy to name. 1.Write down the metal first, then the non-metal. 2.The metal keeps its name. 3.Now take the non-metal, write down its first syllable and then write ide. 4. That’s it! You’re done!

16. Naming Binary Ionic Compounds Example Mg 3 P 2 Magnesium Phosphide Now try these FormulaName Na 2 O AlCl 3 Be 3 S 2

17. More Practice Try these (Name Formula) CompoundSymbols and “Criss-Cross” Formula Calcium Chloride Beryllium Phosphide Aluminum Oxide Potassium Nitride Magnesium Carbide Sodium Iodide Lithium Sulfide

18. Now Try These (Formula Name) FormulaName CaF 2 Al 4 Si 3 Mg 3 P 2 BeI 2 LiF Ca 2 C Na 3 P