Answer:

Explanation:
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In this case, since the radioactive reaction for the alpha emission of astatine-218 to bismith-214 involve the release of a helium atom as shown below:

Whereas the atomic number decreases by 2 and the mass number by 4 in agreement to the release of the Helium atom.
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Answer:
Gasification refers to the conversion of coal to a mixture of gases, including carbon monoxide, hydrogen, methane, and other hydrocarbons, depending on the conditions involved.
So if you put a holo ball of paper in the water it sinks and as it sinks it gets smaller cuse pressure so it cuseus things to shrink cuse of pressure
The atomic radius of main group elements generally increases down a group because as there are more electrons they are farther away from the nucleus and the electrons closer to the nucleus shield the outer electrons from the protons for attraction.
It would likely be HF. It displays hydrogen bonding.