There are 32 valence electrons for the Lewis structure for ClO4
Answer:
"Carbon dioxide (CO2) is one of a number of gases that are transparent to the visible light falling on the Earth from the Sun, but absorb the infra-red radiation (heat) emitted by the warm surface of the Earth, preventing its loss into space. During the geological history of the Earth the level of atmospheric CO2 has varied considerably and this has had an impact on the global temperature. A significant amount of this atmospheric carbon was sequestered or (removed from the atmosphere) and turned into inert material (coal, and oil) typically 300-360 Million years ago. All of the global ecosystems and species have adapted to a lower level of atmospheric CO2 and critically, human civilisation has also grown since that period. Since the industrial revolution humans have been burning sequestered CO2 in the form of coal, oil, and natural gas which has the result of releasing energy but also releases CO2 back into the atmosphere".
The answer is b. radon-222. The alpha decay means that it will emit an alpha particle when decays. The alpha particle has two protons and two neutrons. So Radium(88) minus two protons will become Radon(86). And the atomic mass will become 226-4=222.