Why carbon shares electrons
Gaining or losing four electrons is too hard.
Four to spare
A carbon atom has four electrons in its outermost shell. To have a full outer shell, like a noble gas, it would have to gain four electrons or lose four electrons.
What do you think carbon does instead?
What this lesson covers
The idea
Carbon has four valence electrons; gaining four (C4–) or losing four (C4+) would be very difficult, so carbon attains noble gas configuration by sharing its valence electrons with other atoms.
Four to spare
A carbon atom has four electrons in its outermost shell. To have a full outer shell, like a noble gas, it would have to gain four electrons or lose four electrons.
What do you think carbon does instead?
- It gains four electrons and becomes a C⁴⁻ ion
- It shares its outer electrons with other atoms
- It loses four electrons and becomes a C⁴⁺ ion
Three ways out
Press Next step. Blue dots are inner electrons and red dots are outer electrons.
Sharing is the way out
Gaining four electrons and losing four electrons are both very difficult for carbon. So carbon shares its valence electrons, the electrons in its outermost shell.
Carbon has four valence electrons. Gaining four (C⁴⁻) or losing four (C⁴⁺) would be very difficult, so carbon attains noble gas configuration by sharing its valence electrons with other atoms.
Notes
Carbon has four valence electrons. Gaining four (C⁴⁻) or losing four (C⁴⁺) would be very difficult, so carbon attains noble gas configuration by sharing its valence electrons with other atoms.
Check yourself
How many electrons are in the outermost shell of a carbon atom?
Why is it hard for carbon to form a C⁴⁻ ion?
How does carbon reach a noble gas configuration?
A C⁴⁻ ion has six protons and has gained four electrons. How many electrons does it have?
Answer: 10
6 + 4 = 10 electrons around a nucleus with six protons.
- 2. Two electrons are the inner ones. The outermost shell of carbon has four electrons.
- 4 — correct. Yes!
- 6. Six is the total number of electrons in a carbon atom. Four of them are in the outermost shell.
- It needs a large amount of energy to remove four electrons. That is the problem with C⁴⁺, which loses electrons. C⁴⁻ is formed by gaining four electrons.
- Carbon has no outermost shell electrons. Carbon has four electrons in its outermost shell.
- A nucleus with six protons would have to hold on to ten electrons — correct. Yes!
- By sharing its valence electrons with other atoms — correct. Yes!
- By gaining four electrons. That would make a C⁴⁻ ion, with six protons holding ten electrons. This is difficult.
- By losing four electrons. That would make a C⁴⁺ ion, and removing four electrons needs a large amount of energy.