Answer:
is the isotopic notation of the atom
Explanation:
The isotope notation is:

<em>Where a is the mass number = Number of protons + Number of neutrons</em>
<em>b is atomic number = Number of protons</em>
The atomic number define the nature of the atom, the element with atomic number = 15 is phosphorus, P:

a = 15 protons + 16 neutrons = 31
b = 15
is the isotopic notation of the atom.
Answer:
i think kinetic energy sorry if I'm wrong.
The CH4 molecule has the lowest molecular weight, so it has the lowest boiling point.
Hope I helped :)
Answer:
vigorous
Explanation:
As you go down group one of the periodic table, the reactions become and more vigorous.