The answer is definitely D
Halogens (atoms with 7 valence electrons) and Hydrogen
or generally, atoms with their shells almost full
A single replacement reaction, sometimes called a single displacement reaction, is a reaction in which one element is substituted for another element in a compound. The starting materials are always pure elements, such as a pure zinc metal or hydrogen gas, plus an aqueous compound.
The total amount of solute decreases.
Decomposition reaction D. 2H20⇒ 2H2 + O2
<h3>Further explanation
</h3>
Every chemical reaction involves a compound consisting of reactants and products
Reactants are compounds that react and form new compounds called products
There are several forms of reactions that can occur, including single replacement, double replacement, synthesis, decomposition, etc.
A. 2C2H6 + 702 ⇒ 4CO2 + 6H20
Combustion : reaction of Hydrocarbon and Oxygen
B. AgNO3 + LiCl → AgCl + LINO3
Double replacement : there is an ion exchange between two ion compounds in the reactant to form two new ion compounds in the product
C. Ca + MgS → CaS + Mg
Single replacement :one element replaces the other elements of a compound to produce new elements and compounds
D. 2H20⇒ 2H2 + O2
Decomposition : One compound breaks down into 2 components