Synthesis Reactions
What is a Synthesis Reaction?
-Two smaller pieces join together to produce a larger, more complex compound
-A + B  AB
-Must use same cross charge rules from previous chapter
-Do not forget BrINClHOF – only exist in diatomic states
-Example : Iodine – I2 at all times – use this during reactions and crossing charges
Synthesis with Halogens
-Alkali Metal with Halogen: Find charges from periodic table/required ions chart, add
elements together, cross charges
-Example: Li + Br  LiBr (Li +1, Br -1)
-Alkaline Earth Metal with Halogen: Find charges from periodic table/required ions chart,
add element together, cross charges, PATTERN: two Halogen for one Alkaline Earth Metal
-Example: Mg + Cl  MgCl2 (Mg +2, Cl-1)
-Transition Metal with Halogen: Find charges from periodic table/required ions chart, add
elements together, cross charges, use roman numerals, simplify subscripts
-Example: Fe + I2  FeI3
Synthesis with Oxidation (Oxygen/Sulfur)
- Element + oxide (O2)
- Alkali Metal with Oxide: Find charges from periodic table/required ions chart, add
elements together and cross the charges; have two Alkali Metal ion to one
Oxygen/Sulfur
o Example: Na + O2  Na2O
- Alkaline Earth Metal with Oxgyen: follow above process and naming rules from Halogen
synthesis; always have one of each ion
o Example: Mg + O2  MgO
- Transition Metal with Oxygen: follow normal rules for naming Transition Metals,
depends on the charge of the Transition Metal
o Example: Fe + O2  Fe2O3
- Nonmetal with Oxygen: when combined, nonmetallic oxide is formed
o Example: C + O2  CO2
Synthesis of Metal-Oxides with Water
-Alkali Metallic Oxide with Water: follow naming rules, forms a metal hydroxide of an ion
- Metal hydroxide is a metal and a hydroxide
-Example: Na2O + H2O  NaOH
- Alkaline Earth Metallic Oxide with Water: follow naming rules, forms a metal hydroxide of an ion
with one metal ion and two hydroxide ions
-Example: MgO + H2O  Mg(OH)2
-Transition Metallic Oxide with Water: follow naming rules, forms a metal hydroxide, the ion
number depends on the charge of the transition metal
-Example: Fe2O3 + H2O  Fe(OH)3
-Nonmetallic Oxide with Water: follow naming rules, forms a non-metallic hydroxide
-Example: CO2 + H2O  H2CO3