HELP PLEASE I DONT KNOW WHAT THIS MEANS IM CONFUSED

Explanation:

In an alpha emission, an alpha particle is ejected from a large nucleus. An alpha particle is simply a helium nucleus (atomic number is 2 and mass number is 4) so that means that the atomic number of the emitting nucleus decreases by 2 and its mass number decreases by 4.

because u need two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei to form isotopes.

so since they all have the same shape? i mean maybe because m& m and reeses are both chocolates

increased stability in the completion of fluorine's outer shell.