Writing Formulas for Binary Ionic Compounds. So we have written names for binary ionic compounds. But how do we get their formulas?

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1 So we have written names for binary ionic compounds. But how do we get their formulas?

2 So we have written names for binary ionic compounds. But how do we get their formulas? It is very important to remember that ionic compounds are made up of two oppositely charged particles.

3 So we have written names for binary ionic compounds. But how do we get their formulas? It is very important to remember that ionic compounds are made up of two oppositely charged particles. Therefore ALL ionic compounds are NEUTRAL by nature, ie they have NO left over charge.

4 Therefore ALL ionic compounds are NEUTRAL by nature, ie they have NO left over charge. Take sodium chloride for example. It is made up of one sodium ion and one chloride ion. Na + Cl-

5 Therefore ALL ionic compounds are NEUTRAL by nature, ie they have NO left over charge. Take sodium chloride for example. It is made up of one sodium ion and one chloride ion. Na + Cl- NaCl

6 Therefore ALL ionic compounds are NEUTRAL by nature, ie they have NO left over charge. Or aluminum chloride for example: Al 3+ Cl -

7 Therefore ALL ionic compounds are NEUTRAL by nature, ie they have NO left over charge. Or aluminum chloride for example: Al 3+ Cl - would not make a neutral substance.

8 Therefore ALL ionic compounds are NEUTRAL by nature, ie they have NO left over charge. Or aluminum chloride for example: Al 3+ Cl - Cl - Cl -

9 Therefore ALL ionic compounds are NEUTRAL by nature, ie they have NO left over charge. Or aluminum chloride for example: Al 3+ Cl - Cl - Cl - would be neutral. So the formula would be: AlCl3

10 But writing all of those extra ions can be time consuming. Is there a shorter way?

11 But writing all of those extra ions can be time consuming. Is there a shorter way? Let s try: barium fluoride. Ba 2+ F -

12 But writing all of those extra ions can be time consuming. Is there a shorter way? Let s try: barium fluoride. Ba 2+ F - Take the value of the each charge and simply switch it to the other element.

13 But writing all of those extra ions can be time consuming. Is there a shorter way? Let s try: barium fluoride. Ba 2+ F - Take the value of the each charge and simply switch it to the other element. That gives us BaF2. But is that neutral?

14 But writing all of those extra ions can be time consuming. Is there a shorter way? Let s try: barium fluoride. Ba 2+ F - Take the value of the each charge and simply switch it to the other element. That gives us BaF2. But is that neutral? Well 1 2+ is canceled out by So YES it is neutral.

15 Does it work every time you may ask? Na + O 2- Remember take the value of the each charge and simply switch it to the other element. Ca 2+ S 2- Al 3+ O 2-

16 Does it work every time you may ask? Remember take the value of the each charge and simply switch it to the other element. Na + O 2- Ca 2+ S 2- Al 3+ O 2- Na2O for sodium oxide Ca2S2 becomes CaS for calcium sulfide because ionic compounds are ALWAYS written in lowest terms. Al2O3 for aluminum oxide

17 Even for the elements that use Roman numerals, it works! Ni 2+ Br -

18 Even for the elements that use Roman numerals, it works! Ni 2+ Br - NiBr2 for nickel (II) bromide

19 Formulas for Binary Ionic YOUR TURN: Cl - S 2- P 3- O 2- Li + Mg 2+ Al 3+ Fe 2+ Write the formulas and names for each of the following compounds.