Hydrogen (H-1), deuterium (H-2), and tritium (H-3) are the three isotopes of hydrogen. What are the values of a, b, and c in the table?

Isotope Number of Protons Number of Electrons Number of Neutrons
H-1 1 1 0
H-2 a 1 b
H-3 1 1 c

A.
a = 2, b = 3, c = 2
B.
a = 1, b = 2, c = 3
C.
a = 2, b = 1, c = 3
D.
a = 1, b = 1, c = 2
E.
a = 1, b = 1, c = 1

1 answer

To determine the values of a, b, and c in the table for the isotopes of hydrogen, we need to understand that:

  • The number of protons in an atom determines what element it is. All isotopes of hydrogen have 1 proton.
  • The number of neutrons plus the number of protons gives us the mass number of the isotope.

Let's analyze each isotope:

  1. H-1 (Protium):

    • Number of Protons: 1
    • Number of Electrons: 1
    • Number of Neutrons: 0
    • Mass number = 1 (1 proton + 0 neutrons)
  2. H-2 (Deuterium):

    • Number of Protons: a (which is the same as for all hydrogen isotopes) = 1
    • Number of Electrons: 1 (remains the same since it's neutral)
    • Number of Neutrons: b
    • Mass number = 2 (1 proton + b neutrons), therefore b = 1.
  3. H-3 (Tritium):

    • Number of Protons: 1
    • Number of Electrons: 1 (remains the same since it's neutral)
    • Number of Neutrons: c
    • Mass number = 3 (1 proton + c neutrons), therefore c = 2.

Now we can fill in the values:

  • a = 1 (for H-2)
  • b = 1 (for H-2)
  • c = 2 (for H-3)

So the final answers are:

  • a = 1
  • b = 1
  • c = 2

Therefore, the correct answer is D. a = 1, b = 1, c = 2.