Covalent and ionic bonding and naming molecules and compounds

Transcription

1 Covalent and ionic bonding and naming molecules and compounds

2 ! The periodic table is split into two basic types of elements, metals and non- metals.! The metals are on the le8 side of the periodic table and the non- metals are on the right side of the periodic table.! The metals and non- metals are separated by the stair- case.! All elements along the stair- case are known as metalloids that have proper?es of both metals and non- metals.

3 This le8 side METALS NON- METALS Metalloids

4 Ex. Calcium Metals

5 Tungsten (W) Metals

6 Metalloids Silicon Mirror finished silicon

7 Metalloids Arsenic Arsenic Poisoning

8 Non- metals Chlorine Pale yellow green gas

9 Non- metals Neon - This neon filled discharge tube displays the element's characteris?c reddish- orange emission. Neon normally exists as a colorless gas.

10 Covalent Bonding These are bonds that occur between two (or more) non- metals. We will have to name them and also write the formulae from names Naming Covalent bonds always use prefixes when naming The prefixes are mono (1), di (2), tri (3), tetra (4), penta (5), and hexa (6)

11 You name the first element normally adding a prefix if there are two or more of that element Then, you name the second element ending in - ide using a prefix no mawer how many there are. ex: Name the following: a) CCl 4 b) N 2 O 5 One carbon no prefix Four chlorines tetra prefix di penta carbon tetrachloride dinitrogen pentaoxide

12 Wri6ng Formulae from Names When given a name, simply write the appropriate symbol and number based on what the name says. ex: Write the formulae for: a) dihydrogen monoxide 2 H 1 O H 2 O b) sulfur hexafluoride No prefix = 1 S 6 F SF 6

13 Try these 1. CO 2. N 2 O 3 3. SiF 4 4. diarsenic trisulfide 5. nitrogen tribromide 6. diphosphorous pentoxide 7. diboron hexahydride 8. N 2 S 3 9. Br 2 Check if they are all involved in covalent bonds (non- metal and another non- metal)!!!

14 Ionic Bonding These are bonds between one metal and one or more non- metal. For now, we will focus on the bonds between one metal and one non- metal. Again, we will both name and write formulae for these types of bonds. One major difference from covalent bonds is that ionic bonds NEVER use prefixes!

15 Naming Ionic Bonds To start, you name the first element normally. Then, you name the second element ending in - ide. ex: Name CaBr 2 **NEVER USE PREFIXES** Calcium Bromide

16 Wri6ng Formulae for Ionic Bonds An ion is any charged par?cle. Basically any element on the periodic table can be charged and the main group elements are based on their column number The first column metals will have a charge of +1, the second column +2, then +3, then +/- 4. A8er the fourth column, we get nega?ve ions. The fi8h column is - 3, then - 2, then - 1 and the noble gases have no charge (they can t be ions!)

17 So, in order to write the formula for an ionic bond, you have to first figure out the charges on each ion in the name. Then you switch the number parts (forget about the + and signs). **Make sure a8er you switch the numbers, you put them below the lewers** This will allow you to have a neutral compound (all the posi?ves need to balance out the nega?ves).

18 ex: Write the formulae for: a) Calcium Fluoride second column seventh column Ca 2+ F - 1 CaF 2

19 b) Aluminum sulphide third column sixth column Al 3+ S 2- Al 2 S 3

20 Ionic bonding with transi?on metals These bonds involve metals from the transi?on metals family (middle of the periodic table) Some transi?on metals can carry more than 1 charge, ex. Iron (Fe) can be Fe 2+ or Fe 3+ To show the charge, roman numerals are used. Ex. Iron (II) Oxide Because of the (II), Iron has a 2+ charge Therefore, Fe 2+ O 2- FeO

21 Ionic bonding with transi?on metals Ex. Ex. Iron (III) oxide Fe 3+ O 2- Fe 2 O 3 So the roman numerals do play a big part! Copper (II) Fluoride

22 Ionic bonding with transi?on metals Going backwards Au 2 O 3 What kind of bond? Ionic bond Au is Gold F is Fluorine Gold is a transi?on metal so we need roman numerals. The roman numerals will be the number found on the opposite element. Gold(III) Oxide

23 Complex Ionic Bonds These involve the reac?on between one metal and a complex ion made of 2 or more non- metals Naming is the same as before but the second part doesn t end in - ide but rather it s named using the complex ion chart. Wri?ng formulae works the same but you should always put a complex ion in brackets before you criss- cross.

24 ex: Name CaSO 4 Calcium Sulphate ex 2: Name Al(CH 3 COO) 3 Aluminum Acetate ** S?ll NO prefixes**

25 ex 3: What s the formula for sodium carbonate? Na +1 (CO 3 ) - 2 Na 2 (CO 3 ) ex 4: What s the formula for aluminum chromate? Al +3 (CrO 4 ) - 2 Al 2 (CrO 4 ) 3