The correct answer is A.
B is incorrect because that only applies to nuclear fission.
C is incorrect because it only applies to nuclear fusion.
D is incorrect because energy can be neither created nor destroyed meaning that this statement is physically impossible,
For radioactive decay, we can relate current amount, initial amount, decay constant and time using:
N = No x exp(-λt)
Half-life = ln(2)/λ
λ = ln(2) / 5730
N/No = 80% = 0.8
0.8 = exp( -ln(2)/5730 x t)
t = 1844 years
MgCl2 = 1Mg + 2Cl = 1(24.3) + 2(35.45) = 95.2g/1mole
7.50moles MgCl2 x 95.2g MgCl2 = 714g MgCl2
The periodic table is one of the most important tools in the history of chemistry. It describes the atomic properties of every known chemical element in a concise format, including the atomic number, atomic mass and relationships between the elements. Elements with similar chemical properties are arranged in columns in the periodic table.
The table thus is a quick reference as to what elements may behave the same chemically or which may have similar weights or atomic structures.
Hope this answer helps you
Answer:
Solids, liquids, and gases are made of tiny particles called atoms and molecules. In a solid, the particles are very attracted to each other. They are close together and vibrate in position but don't move past one another. In a liquid, the particles are attracted to each other but not as much as they are in a solid.