Answer:
1-Mg+O2=reactants MgO-product
2-CaNr2+AlCl3=reactants CaCI2+AIBr3=product
3-C2H4+O2=reactants H2O+CO2=product
Explanation:
Reactants are on the left side and products on the right.
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
These animals are all invertebrates
The greenhouse effect is rightly called that because greenhouses allow heat to enter, but doesn't allow heat to leave, which warms plants.
On earth however, it's much bigger. Our own atmosphere acts similarly to this; it allows heat in, but doesn't allow it to leave which heats up the planet and causes global warming.
Usually (ignoring transition metals, as they kinda get trickier), the element's valency can be found out by its group (column) number. Usually, we ignore the transition metal block while counting these columns, so Aluminium is in group 3, for example. Since Aluminium is in group 3, it has 3 valence electrons.