You can not hear sound in vacuumed places like space. Wherever there is a high altitude, it makes it harder to hear sound and harder to breathe. Sound travels best in solids. Hope that helps a little bit.
The first man-made element or artificial element which is produced because it is not found naturally in nature is Technicium, in 1937. Technicium has an atomic number of 43 and atomic mass of 98 g/mol.
You didn't post the whole question. However the answer would be : Mg, according to former questions in this website.
Hope this helps !
Photon
Answer:
58.44 g/mol
Explanation:
just got done with this unit two weeks ago
