Question

Arrange the isotopes of sulfur and phosphorus in order of decreasing number of neutrons.
Rank the isotopes from most to fewest neutrons. To rank items as equivalent, overlap them.

S-36
P-35
S-32
P-33
P-32
P-31

Answer 1

The atomic number of sulfur is 16. So each sulfur will always contain 16 protons.
The atomic number of phosphorous is 15. So each sulfur will always contain 15 protons.
S-36: 36=total amount of protons and neutrons. 36-16=20 neutrons
P-35: 35-15 = 20 Neutrons
S-32: 32-16=16 neutrons
P-33: 33-15=18neutrons
P-32: 32-15 = 17neutrons
P-31: 31-15 = 16neutrons
Ranking: S-36, P-35, P-33, P-32, S-32, P-31

Answer 2

S-36 = P-35 > P-33 > P-32 > S-32=P-31

Answer 3

P-36>P-35>p-34>P-33>P>32>p-31>

Answer 4

The number after the elemental symbol is the total number of protons and neutrons in the nucleus.

The # protons of an element will always stay the same no matter what the isotope is. As well, the # of protons present is equal to the atomic number of theelement.

For example, the atomic number of chlorine is 17. So there will always be 17 protons in a chlorine atom.

Cl-37. This means the number of protons and neutrons is equal to 37. We know there's 17 protons in each chlorine, so that leaves us with 20 neutrons.(37-17=20)
Cl-35 : Do the same thing. 35-17=18 neutrons

The atomic number of sulfur is 16. So each sulfur will always contain 16 protons.
S-36: 36=total amount of protons and neutrons. 36-16=20 neutrons
S-33: 33-16=17 neutrons
S-34: 34-16=18neutrons
S-32: 32-16=16neutrons

So putting these in order:
Cl-37; S-36 (20 neutrons)
S-34; Cl-35 (18 neutrons)
S-33 (17 neutrons)
S-32 (16 neutrons)