1. BACK Binary Ionic How to write compound formulae Multivalent PolyatomicCovalent Nicholas Tang Select a type of compound! Home Binary Ionic CovalentPolyatomic Multivalent Na Zn Al K Mg Li Ba La +2 +3 +2 +1 +2 +3 +1 +4 +7 Au Co Cu Ru Si Hg Sb N C P F H Cl O Br I CO 3 2- CN - CIO - MnO 4 - PO 3 3- HSO 4 -

2. BACK Binary Ionic How to write compound formulae Multivalent PolyatomicCovalent Nicholas Tang Binary Ionic Compounds A binary ionic compound is made of 2 elements, a metal and a non-metal, where both elements have only one ion charge (+1, +2, +3…) Some examples are: Sodium (Na), Potassium (K) and Aluminium (Al). In all compounds, the positive ion (usually a metal) is named first and the negative ion (non-metal) is named second. Example: Magnesium Nitride Mg 2+ N 3- Mg 2+ Mg 3 N 2 Magnesium has a positive charge of 2 Nitrogen has a negative charge of 3 You need 3 Magnesium and 2 Nitrogen to balance even out There are 3 magnesium ions There are 2 Nitrogen ions You change the ending of “Nitrogen” by adding a “ide” to it.

3. BACK Binary Ionic How to write compound formulae Multivalent PolyatomicCovalent Nicholas Tang Multivalent Compounds Multivalent compounds are made of a metal and a non-metal. It is called “multivalent” because it the metal has more than 1 electrical charge (+1, +2…). In order to identify the ion charge, there will be a roman numeral next to the name: gold (III) oxide, copper (I) fluoride Example: platinum (II) nitride Pt 2+ N 3- Pt 2+ 1 – I 2 – II 3 – III 4 – IV 5 – V 6 – VI 7 – VII 8 – VIII 9 – IX 10 - X Pt 3 N 2 Platinum has 2 charges, +2 and +4 The name tells us that we are using the +2 charge (II). Pt 2+ x 3 = 6 N 3- x 2 = 6 It evens out on both sides There are 3 platinum ions There are 2 nitrogen ions It could also be Pt 3 N 4 if the name was platinum (IV) nitride

4. BACK Binary Ionic How to write compound formulae Multivalent PolyatomicCovalent Nicholas Tang Polyatomic Compounds Polyatomic compounds are compounds that contain a polyatomic ion. Polyatomic ions are created when a number of atoms come together to form a group, and then that group can have either a positive or a negative charge. Some examples are: Nitrate (NO 3 - ), Ammonium (NH 4 + ) and Hydroxide (OH - ). Example: Calcium Nitrate Ca 2+ NO 3 - NO 3 - You need 2 Nitrate to even out Ca(NO 3 ) 2 There is 1 Calcium You need to put “Nitrate” in brackets because there is more than 1 There are 2 Nitrate ions in the compound Calcium has a positive charge of 2 Nitrate has a negative charge of 1

5. BACK Binary Ionic How to write compound formulae Multivalent PolyatomicCovalent Nicholas Tang Covalent compounds are compounds made of two or more non-metals. They are made when two or more non-metals share electrons and the bond that is created by sharing electrons is called a “covalent bond.” Some examples are: Oxygen (O), Fluorine (F) and Nitrogen (N). Example: Carbon Dioxide C +1 O 2- O 2- Covalent Compounds CO 2 There is one carbon “Di” mean “2.” So there is 2 oxygen Everything you have learned so far can go into the trash for this one 1 – mono 2- di 3 – tri 4 – tetra 5 – hexa 7 – hepta 8 – octa 9 – nono 10 - deca CO 2 Carbon Dioxide You don’t put “mono” in front of the first word There is 2 oxygen, so you put “di” in front of the name There is 1 carbon There is 2 oxygen If you have “ao” or “oo,” turn it into “o:” heptoxide