Question

C\(^ {126}\) and C\(^ {14}\) are:

• A. Isotopes
• B. Isobars
• C. Isomers
• D. Molecules

Hint:

Isotopes of an element have the same chemical properties but different physical properties due to their varying mass numbers.

Answer 1

The Correct Option is A

Step 1: Count protons and neutrons.
C-12 has 6 protons and 6 neutrons, while C-14 has 6 protons and 8 neutrons.

Step 2: Match the definition.
Same proton count with a different neutron count, and therefore a different mass number, is the definition of isotopes, not isobars, isomers, or molecules.

Step 3: Final Answer.
C-12 and C-14 are Isotopes.

Answer 2

Before even counting protons and neutrons, two of the four options can be ruled out just from what C-12 and C-14 actually are.

1. Isomers: This term only applies to molecules that share a formula but differ in structure. C-12 and C-14 are individual atoms, not molecules, so this option is ruled out immediately.
2. Molecules: A molecule needs at least two atoms bonded together. C-12 and C-14 are each a single atom, so neither one is a molecule, ruling this option out too.
3. Isobars: With those two ruled out, only isotopes and isobars remain. Isobars need different elements sharing one mass number, but C-12 and C-14 are both carbon, the same element, and their mass numbers, 12 and 14, are different, so this option fails on both requirements.
4. Isotopes: Since both atoms are the same element, carbon, but have different mass numbers, exactly matching the definition of isotopes, this is the only option left standing after the other three are eliminated.

Ruling out molecules and isomers first, then isobars, leaves isotopes as the only term that correctly classifies C-12 and C-14.

So the correct answer is Isotopes.