Why is Carbon, the building block of life, safe when eating or drinking (carbonated water), but not when breathing (carbon monoxide or carbon dioxide)?

Question

Why is Carbon, the building block of life, safe when eating or drinking (carbonated water), but not when breathing (carbon monoxide or carbon dioxide)?

In: Biology

Answer 1

ELI5: The properties of compounds/molecules can be COMPLETELY different than the properties of the element.

* Element: The basic building blocks of life, carbon, nitrogen, hydrogen.
* Molecule: Take multiple elements and put them together into something like CO2, CO, etc.

Elements and molecules have COMPLETELY different properties. An element inside of a molecule can be toxic, but because it’s in the molecule it’s perfectly safe.

ELI’m Older: Elements are made of atoms. Atoms are the basic building blocks of life. Atoms are made of protons, neutrons, and electrons. The NUMBER OF electrons determine an atom’s properties. It’s reactivity, how stable it is, etc. When two or more atoms come together to make a molecule, the electrons move around and change. Some move closer to one atom, some move away from another atom. This change makes the MOLECULE have completely different properties than the atom, TYPICALLY because when two or more atoms come together they do so because it’s more STABLE for them to hold onto each other than to be lone atoms. (SOME atoms are super dangerous/reactive because they WANT more electrons, some are super dangerous/reactive because they have TOO MANY electrons. When you pair an element from each of these two groups together, they become MUCH LESS reactive because the element with too many electrons gave it’s extra electrons to the element that wanted electrons.)

The best example I can think of is salt. Literally sodium chloride. Alone, both sodium and chloride are extraordinarily dangerous elements. Sodium explodes on contact with water, and chlorine forms chlorine gas which was used as a weapon of war. But TOGETHER, they form a nice stable, non reactive compound that we consume everyday. This is also why it’s not a huge deal when a seemingly dangerous element (say, mercury or arsenic or sulfur) is sometimes used in things that humans consume. So long as the molecule that contains that element is safe, it’s not an issue.

TL;DR: Molecules (made up of 2 or more atoms (elements)) have completely different properties than the atoms that they are made of due to changes in the position/number of electrons.