Answer:
Hydrogen
Explanation:
A reducing agent is a substance which gives up its electrons to become oxidized. Generally, metals are oxidized (reducing agents) while non-metals are reduced (oxidizing agents).
However, hydrogen which is a non-metal is usually oxidized in the presence of stronger oxidizing non-metals such as fluorine and oxygen.
Hydrogen thus, acts as a reducing agent by giving up its electrons to become oxidized. Even though among all non-metals, Hydrogen has the greatest potential to be oxidized, it is a poor reducing agent compared to reactive metals.
Atomic elements consist of a nucleus that contains protons and neutrons. Protons carry a positive charge whilst neutrons are electrically neutral. In light elements with an atomic number less than 20, the neutron to proton ratio is generally equal to 1:1. This changes for heavier elements since the Coulomb interaction between many protons gets stronger and demands more neutrons for the nucleus to remain stable.
Explanation:If the mass of the object stays the same but the volume of the object decreases then its density becomes greater. If the volume of the object stays the same but the mass of the object increases then its density becomes greater.
The third one is correct, not sure abt another one