Year 9 Science · Unit 2 · Lesson 06
Challenge Worksheet
Learning Goals
What if…?
Scenario
Carbon (C, Z=6) has the electron configuration 2,4, it has 4 valence electrons, exactly halfway between gaining 4 and losing 4. In reality, carbon almost always reaches stability by sharing electrons (covalent bonding), not by losing or gaining them. But what if carbon always lost 4 electrons to become stable, just like sodium loses 1, forming a C⁴⁺ ion instead of sharing electrons? What would change about the chemistry of carbon?
Using what you know about electron configuration, electron transfer, and chemical bonding, predict and explain what would change if carbon always lost 4 electrons rather than sharing them. In your answer consider: (i) what type of bonds carbon would form; (ii) whether molecules like CO₂, glucose (C₆H₁₂O₆), and DNA could still exist; (iii) what this would mean for the existence of organic chemistry and life as we know it. Use scientific terms throughout.
1. Why do noble gases almost never form compounds? Use electron configuration to explain your answer clearly. Then identify one exception: xenon difluoride (XeF₂) is a real compound that exists. Suggest why xenon, unlike helium or neon, is able to form a compound with fluorine under extreme conditions. (Hint: consider xenon's size, the number of shells it has, and fluorine's extreme reactivity.)
2. A student claims: "All atoms want to have 8 electrons in their outer shell, that is the only way to become stable." Identify two problems with this claim, using specific examples from elements you have studied in this lesson to support your argument.
Wrap Up
In one sentence, what was the main idea of this lesson?