Your answer should be C.) +2. "All the elements in Group 2 have two electrons in their valence shells, giving them an oxidation state of +2."
Credits: https://chem.libretexts.org/Core/Inorganic_Chemistry/Descriptive_Chemistry/Elements_Organized_by_Blo...
Hopefully this has helped! :)
Answer:
Group 7 or the Halogens
Explanation:
The halogens occupies the 7th group on the periodic table. The group is made of F, Cl , Br, I and At.
The elements in this group are the most reactive of all elements. They are very reactive because they have just 7 electrons in their outermost shell and they only require an electron to complete their electronic configuration to produce an octet which typically mimics the stable group VIII elements.
This makes them very highly reactive.
Water. All organisms that depend on oxygen need water to live.
This question asks to compare the energy emitted by a piece of iron at T = 603K with the energy emitted by the same piece at T = 298K.
Then you need to use the Stefan–Boltzmann Law
That law states that energy emitted (E) is proportional to fourth power of the to the absolute temperature (T), this is E α T^4 (the sign α is used to express proportionallity.
Then E (603) / E (298) = [603K / 298K]^4 = 16,8
Which meand that the Energy emitted at 603 K is 16,8 times the energy emitted at 298K.