Question

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

Answer 1

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**.