<span>Groups are vertical, numbered 1 through 18, and have similar properties, so answer D. Most of the properties of groups are defined by the outermost electron in the shells of the elements. Horizontal delineations in the Periodic Table are known as periods.</span>
The radioactive decay obeys first order kinetics
the rate law expression for radioactive decay is
![ln\frac{[A_{0}]}{[A_{t}]}=kt](https://tex.z-dn.net/?f=ln%5Cfrac%7B%5BA_%7B0%7D%5D%7D%7B%5BA_%7Bt%7D%5D%7D%3Dkt)
Where
A0 = initial concentration
At = concentration after time "t"
t = time
k = rate constant
For first order reaction the relation between rate constant and half life is:
Let us calculate k
k = 0.693 / 72 = 0.009625 years⁻¹
Given
At = 0.25 A0
time = 144 years
So after 144 years the sample contains 25% parent isotope and 75% daughter isotopes**
Simply two half lives
Green plants transform solar energy<span> to </span>chemical energy<span> (mostly of oxygen) through the </span>process<span> known as photosynthesis, and electrical </span>energy<span> can be converted to </span>chemical energy<span> and vice versa through electrochemical reactions.</span>
The product in this chemical reaction is Carbon Dioxide or CO2.
This is because it states, "To form," which means that it was produced from the reactants Carbon and Oxygen.
To know what the products are in a statement rather than an equation, words such as produced and formed are used.
Hope this helps!
