Elements always exist as pair of atoms called molecules .
Explanation:-
- The material which has only one types of similar atoms called element .
- Ex:-Sodium,Carbon etc
D is the answer cause two h20 + o2(g)
Answer : The formula of the missing product is, 
Explanation :
The given incomplete equation representing a reaction,

When the sodium metal react with the water then it gives a colorless solution of sodium hydroxide and hydrogen gas. In the solution, sodium hydroxide is present in the form of ions i.e,
and
ions.
The balanced chemical reaction will be,

Therefore, the formula of the missing product is, 
Iam willing to play truth and dare
Explanation:
because I love to play truth and dare