1. What type of reaction is this? H2O + H2 + O2
A. Synthesis
B. Decomposition
C. Combustion
D. Single Replacement
E. Double Replacement

I say synthesis

B if you meant ->

Explanation:

A. Synthesis: reaction where two or more reactants combine to form one product. A+B->AB

B. Decomposition: reaction where a single compound reacts to form more than one product. AB-> A+B

C. Combustion: any reaction in which a substance reacts with oxygen gas. (needs )

D. Single replacement: a type of reaction where one element replaces a similar element within a compound. Reaction is always an element and a compound.

E. Double replacement: a type of reaction where the ions of two compounds exchange places in an aqueous solution to form two new compounds. AB+CD->AD+CD

increased stability in the completion of fluorine's outer shell.

each  column  of the  table  is called a group. elements in a group share similar properties. groups are  read  from  top  to  bottom. metal. metalloid. nonmetal. solid. liquid. gas. fe. hg. o.  2. 3. 4. 5. 6. 7. 8. 9.  2. beryllium. 9.012. 4.  sodium. 22.990.  11. 3.  magnesium. 24.305.  12.  potassium. 39.098.  19. 4.  calcium. 40.078.  20. i guess  i