Wikipedia:Reference desk/Archives/Science/2021 September 16

Welcome to the Wikipedia Science Reference Desk Archives
The page you are currently viewing is a transcluded archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

September 16

Why there is no vent for medical oxygen tanks?

I remember seeing a vent on top of oxygen tanks at industries, but why there is no vent for medical oxygen tanks? Rizosome (talk) 03:49, 16 September 2021 (UTC)

Maybe the venting oxygen tanks you saw were for holding liquid oxygen, whereas medical oxygen tanks contain compressed gas. Here you can read about the need to vent liquid oxygen cylinders.  --Lambiam 07:05, 17 September 2021 (UTC)

A great link. Just to add that liquid oxygen would be far too cold to use in a medical setting, e.g. to assist breathing.--Shantavira|^{feed me} 08:28, 17 September 2021 (UTC)

For iron's metallic bond, what type of iron ion is present to bond with the delocalized electrons?

For sodium, each Na will lose 1 e- to form Na+. Then sodium ions are attracted to the delocalized electrons, and therefore there is metallic bond. However, for iron (and other transition metals), how many electrons will each iron atom lose? Will they lose all of the 4s electrons? Or, is the ion Fe(II) or Fe(III) ion? Thank you so much!!!! Jocosus2000 (talk) 15:04, 16 September 2021 (UTC)

• NaCl has ionic bonds. Those can be simplified as "one atom loses one (or more) electron(s) to another atom, and both stick together due to electromagnetic attraction". (For the longer explanation, see the linked article.)

Iron, on the other hand, has metallic bonding. A gross oversimplification is that iron atoms pool electrons together into a sea of free-moving electrons. Individual atoms do not really "lose" electrons in that process. How many free electrons per atom are yielded by that process is a good question, but not one I can answer - researching this probably goes through our article Valence and conduction bands; based on a sentence in Drude model I assume usually as many as the valence number (so, probably 3?).

Finally, many compounds have covalent bonding, where close-by atoms share some electrons, and shared electrons count for both atoms towards the "having a complete electronic shell" stability criterion. The difference with metallic bonding is that the electrons are not free-moving so the bond is really local. Tigraan^{Click here for my talk page ("private" contact)} 15:52, 16 September 2021 (UTC)

Thank you so much!!! By the way, is band similar to orbitals? Thanks:)Jocosus2000 (talk) 10:04, 17 September 2021 (UTC)

No. Atomic orbitals are a concept linked to a single atom (the "location" of a given electron, basically). The conduction/valence bands are macroscopic (or mesoscopic) concepts related to energy levels of a large number of electrons around a large number of atoms. Tigraan^{Click here for my talk page ("private" contact)} 12:06, 17 September 2021 (UTC)

Where an atom in a compound loses an electron to some other place in the structure, and it is just a single electron, that is called an electride. They're different to metals as they are insulators. Graeme Bartlett (talk) 12:41, 17 September 2021 (UTC)

Thank you so much! Jocosus2000 (talk) 15:20, 17 September 2021 (UTC)