What percent of potassium-40 remains undecayed in a rock that is 3.9 billion years old? The 3.9 billion year old rock has undergone three half-lives (3.9 divided by 1.3 = 3). After 3 half-lives, 12.5% of the potassium-40 remains undecayed.
Answer : A metal in group 16 of the periodic table can become a chemically stable ion by gaining 2 electrons.
Explanation :
The group 16 element are oxygen, sulfur, selenium, tellurium and polonium.
The general electronic configuration of group 16 elements is, ![ns^2np^4](https://tex.z-dn.net/?f=ns%5E2np%5E4)
As we now that there are total 6 electrons in p sub-shell. So, a metal in group 16 can become a chemically stable ion by gaining 2 electrons.
![M+2e^-\rightarrow M^{-2}](https://tex.z-dn.net/?f=M%2B2e%5E-%5Crightarrow%20M%5E%7B-2%7D)
Hence, a metal in group 16 of the periodic table can become a chemically stable ion by gaining 2 electrons.
Hi!
Gene therapy can be used to introduce foreign DNA into cells of tissues to cure inheritable disease.
Answer:
A option mantle is correct I guess
hope this helps u
Answer:
yes, Y = 1.2x yan po ata hehehehehe tangkyou po sa question......