1 Compounds and chemical formulas 4.3

2 Characteristics of Ionic bonds charge ions. A bond formed by the transfer of 2 oppositely charged ions charge ions. A bond formed by the transfer of 2 oppositely charged ions Metals Non metals Metals Non metals + ions- ions Cationsanions Lose e-gain e- Lose e-gain e- +charge- charge L/sideR/side

3 Characteristics of Ionic compounds Elements in group one have a 1+ ion charge Elements in group one have a 1+ ion charge ex: Na, Li, K Elements in group two have a 2+ ion charge Elements in group two have a 2+ ion charge ex. Be, Ca, Sr Elements in group thirteen have a 3+ ion charge. Elements in group thirteen have a 3+ ion charge. ex. Al, B, Ga

4 Characteristics of Ionic Compounds Elements in group17 have a 1- ion charge Elements in group17 have a 1- ion charge ex. Cl, Br, I Elements in group 16 have a 2- ion charge Elements in group 16 have a 2- ion charge ex. O, S, Te Elements is group 15 have a 3- ion charge ex. N, P, Bi

5 Naming Ionic Compounds ( two elements) Step one – Name the first element in the formula Step one – Name the first element in the formula Ex. NaCl – Sodium Step two – Name the second element Step two – Name the second element Ex. NaCl – Sodium Chlorine Step three – Add a –ide ending to the second element. Step three – Add a –ide ending to the second element. Ex. NaCl – Sodium Chloride

6 Writing Ionic Compounds Step 1 Write both positive and negative ions Ca 2+ F -

7 Writing Ionic Compounds Step 2 Cross charges down, making subscripts Ca 2+ F - Ca 1- F 2+

8 Writing Ionic Compounds Step 3 Drop the charges and combine your new compound. CaF 2

9 Summary Formula Writing for Ionic Bonds Criss Cross Method Criss Cross Method Sodium Cloride Sodium Cloride 1. Write symbol of 2 elements ( Na Cl) 1. Write symbol of 2 elements ( Na Cl) 2. Write their ionic charges as superscripts 2. Write their ionic charges as superscripts (Na +1 Cl -1 ) Criss Cross Charges making subscripts & drop superscripts& drop the signs (NaCl)

10 Characteistics of Covalent Bonds Formed when atoms share one or more e- Formed when atoms share one or more e- Formed between Non-metals Formed between Non-metals So they are usually formed between elements on the right side of the periodic table So they are usually formed between elements on the right side of the periodic table Anions Anions - charge - charge

11 Characteristics of Covalent Bonds They are poor conductors of electricity They are poor conductors of electricity Covalent bonds are also called Molecules! Covalent bonds are also called Molecules! Prefixes p. 126, write out Prefixes p. 126, write out Id non metals on PC Id non metals on PC Develop a hydrogen bond Develop a hydrogen bond

12 Naming Covalent Compounds Mono - 1 Mono - 1 Di - 2 Di - 2 Tri - 3 Tri - 3 Tetra - 4 Tetra - 4 Penta - 5 Penta - 5 Hexa - 6 Hepta - 7 Octa - 8 Nona - 9 Deca – 10 Practice p. 56

13 Characteristics of Polyatomic ion An ion made of two or more atoms that are covalently bonded and that act like a single ion. An ion made of two or more atoms that are covalently bonded and that act like a single ion. Covalent and ionic Covalent and ionic

14 Writing Polyatomic ion RULES Must ALWAYS use Parentheses Leave the charge outside the Parentheses Table 4-3 page 122 – list of common ions File card Polys C/W p. 57 and 44

15 Characteristics of Transition Metals Group 3-12 have multiple charges depending on the nonmetal they are bonding with. Group 3-12 have multiple charges depending on the nonmetal they are bonding with. Ex. Fe 2 O 3 and FeO are different compounds Fe 3+ O 2- = Fe 2 O 3 Fe 3+ O 2- = Fe 2 O 3 Fe 2+ O 2- = Fe 2 O 2 = FeO Fe 2+ O 2- = Fe 2 O 2 = FeO

16 Writing and Naming Transition Metals ROMAN NUMERALS ROMAN NUMERALS Same naming scheme as ordinary binary compounds Same naming scheme as ordinary binary compounds Add a Roman Numeral to identify the charge of the metal Add a Roman Numeral to identify the charge of the metal Ex Fe 2 O 3 = iron(III)Oxide FeO = iron(II)Oxide Practice boards and p.55 Practice boards and p.55

17 Compounds Ionic Covelant Ionic Covelant Polyatomic Polyatomic Transition Transition

18 Empirical Formula The simplest chemical formula of a compound that tells the smallest whole-number ratio of atoms in the compound.

19 Molecular Formula A chemical formula that reports the actual numbers of atoms in one molecule of a compound.