The mass would be 28. The mass of an atom equals the number of neutrons and protons added together. In this case, they do not say the protons. But we must use our inside knowledge to know that the number of protons equals the number of electrons. Thus, your number of protons would be 13
Answer: Compound
Explanation:
Element is a pure substance which is composed of atoms of similar elements.It can not be decomposed into simpler constituents using chemical reactions.Example: Copper 
Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.It can be decomposed into simpler constituents using chemical reactions. Example: water 
Thus as it give that the red sample on being heated, a gas is released and a blue powder is left after the heating. Thus the given sample is a compound.
Flame colors are produced from the movement of the electrons in the metal ions present in the compounds. When you heat it, the electrons gain energy and can jump into any of the empty orbitals at higher levels Each of these jumps involves a specific amount of energy being released as light energy, and each corresponds to a particular color. As a result of all these jumps, a spectrum of colored lines will be produced. The color you see will be a combination of all these individual colors.
<u>Answer and Explanation:</u>
Mercury combines with sulfur as follows -
Hg + S = HgS
Hg = 200,59
S = 32,066 Therefore 1.58 g of Hg will react with -
1.58 multiply with 32,066 divide by 200,96 of sulfur.
= 0.25211 g S
This will form 1.58 + 0.25211 g HgS = 1.83211 g HgS
The amount of S remaining = 1.10 - 0.25211 = 0.84789 g
