Isotopes & Identity
Topic 2.3.1-2.3.3: Same Element, Different Mass
The Isotope Rule
Isotopes are atoms of the same element (same protons) with different neutrons. Think of them as identical twins wearing different backpacks— the twin's identity doesn't change just because one carries more weight!
The Neutron Loading Dock
Add or remove neutrons. Watch the mass change — but the element stays Carbon!
Symbol Decoder
Click on the numbers to decode the isotope notation
Notation Guide:
Stability & Radioactivity
✓ Stable Isotopes
Carbon-12 and Carbon-13 have balanced proton-to-neutron ratios. Their nuclei are stable and do not decay.
☢ Radioactive Isotopes
Carbon-14 has too many neutrons. The nucleus is unstable and will eventually emit radiation to become more stable (radioactive decay).
🔑 Key Takeaway:
Even though C-14 is radioactive, it still reacts chemically exactly like C-12 and C-13 because all have the same electron configuration. Nuclear instability ≠ Chemical reactivity!
Examiner's Wisdom
Isotopes of the same element have identical chemical properties because they have the same number of electrons.
To calculate neutrons: N = A - Z
The atomic number (Z) defines the element. Change Z → Different element!
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