I believe its a covalent bond?
I think the answer is molecule
I believe both C) and D) are correct, because both have enough electrons to show that the element has enough protons to be a transition metal, and both elements seem to have an electron configuration that exists in the ground state. We may need more information.
Answer:
: conjugate acid of 
: conjugate base of 
: conjugate base of 
: conjugate acid of 
Explanation:
According to the Bronsted-Lowry conjugate acid-base theory, an acid is defined as a substance which looses donates protons and thus forming conjugate base and a base is defined as a substance which accepts protons and thus forming conjugate acid.

Here in forward reaction
is accepting a proton, thus it is considered as a base and after accepting a proton, it forms
which is a conjugate acid.
And
is losing a proton, thus it is considered as an acid and after loosing a proton, it forms
which is a conjugate base.
Similarly in the backward reaction,
is loosing a proton, thus it is considered as a acid and after loosing a proton, it forms
which is a conjugate base.
And
is accepting a proton, thus it is considered as a base and after accepting a proton, it forms
which is a conjugate acid.
Answer:
A. Students made a measurement error, because ending with more products is impossible.
Explanation:
The law of conversation of matter tells us that in a chemical reaction, matter is never created or destroyed, it's simply converted from one form to another. So the mass of reactants should always equal the mass of the products in a chemical reaction. If there is excess mass in the product, the students have made an error of some kind.