Chemistry helpppp????? pleaseeeee??

Question

the 37CL-1 isotope contains:

A) 17 protons, 20 neutrons and 17 electrons

B) 17 protons, 20 neutrons and 18 electrons

C) 17 protons 37 neutrons and 18 electrons

D) 37 protons 37 neurons and 38 electrons

Please helpppppp

Answer 1

37 refers to the atomic mass meaning the sum of the particles in the nucleus. The nucleus consits of protons and neutron which add up to 37, immediately you can rule out the last two choices. Now the problem does not state that this is an ion so the number of electrons should be the same as in the original chlorine, so the only thing that changes and specifies an isotope is the number of neutrons. The answer is A. Hope this helps.

Answer 2

The atomic weight of an element is the sum of its protons and neutrons. In an element ( not an ion of the element ) the number of electrons equals the number of protons = atomic number, In the case cited above Cl^-1 is chloride anion and it has one extra electron than the element Cl so 37Cl^1   has 17 protons , 18 electrons and 20 neutrons  answer B