Answer:
The correct option is;
Group 12
Explanation:
A metallic element that is shiny and silver colored that can exist in the +1 and +2 ionic states and which forms a bright red compound with sulfur is mercury, Hg
The compound formed between mercury and silver is one of the earliest synthetic compound also known as vermilion and cinnabar. The bright red pigment of the HgS is used widely and is one of the most favorite pigment found in medieval European outstanding works of arts and in Chinese decorated wares made of lacquer as well as in mesoAmerica.
Answer and Explanation:
The balanced chemical equations are as follows:
The chemical formula of oxalic is 
In the case when oxalic acts reacted with the water so here the oxalic acid eliminates one proton that leads to the development of mono acids
After that, the second step derives that when oxalic acid is in aqueous solution eliminates other proton so it represent the polyprotic acid
Now the chemical equations are as follows:
Elimination of one proton

Now the elimination of other proton

Answer:
a process that involves rearrangement of the molecular or ionic structure of a substance, as distinct from a change in physical form or a nuclear reaction
I'm pretty sure all 4 are subatomic particles but if i had to guess i'd be Photons