Answer: 20 mg Te-99 remains after 12 hours.
Explanation: N(t) = N(0)*(1/2)^(t/t1/2)
N(t) = (80 mg)*(0.5)^(12/6)
N(t) = 20 mg remains after 12 hours
The answer is B. because it starts at Conifer Seeds and ends at Northern goshawks.
Answer:
Answers are bellow.
Explanation:
The element with electron configuration 1s22s22p63s1 belong I A group in the periodic table and it is sodium because it loses one electron.
We have periodic table in attachments.
Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table, because it has a single electron in its outer shell, which it readily donates, creating a positively charged ion—the Na+ cation. Its only stable isotope is 23Na.
The free metal does not occur in nature, and must be prepared from compounds.
It is soft metal, reactive and with a low melting point.
Well, the sun is in space, right? It has to be able to transfer heat through space, or how would it get to us? Radiation helps transfer heat.
The terms that apply to this silver necklace are:
pure chemical substance
element
The necklace consists purely of silver, making it a pure chemical substance; moreover, silver itself is an element, not a compound. Therefore, the term element is also fitting for the necklace.