Sure it'd be great if we could do that but reality doesn't really work that way. Post memes/jokes in /r/chemistrymemes and /r/chemistryjokes. Any such posts will be deleted.Īsk education and jobs questions in the current weekly topic. If you're looking for a more concentrated, advanced discussion of chemistry topics among professionals and grad students, check out /r/Chempros.īefore asking "What chemical is this?" see this chart. Click here for the OSHA chemical data site and here for a multicompany MSDS aggregate search. If you spill/injure yourself contact medical professionals and read the MSDS, do not post to this reddit. Yes links to blogs, images, videos, comics, and infographics are okay especially if they are on your personal website. No physorg, sciencedaily, or other press release aggregator spam! If a caption or explanation is included this helps, but please use your discretion.īefore asking about chemical drawing/illustration programs, look at your school's IT/software website and see if they provide an institutional license of ChemDraw (hint: if they have a chemistry department, they will) Likewise, simple pictures of uninteresting and garden variety chemistry-related things are not appreciated. No memes, rage comics, image macros, reaction gifs, or other "zero-content" material. However, academic discussions on pharmaceutical chemistry and the science of explosives are permitted. Rules: Violating a rule will result in a ban.Īsk homework, exam, lab, and other undergraduate-level questions at ChemicalForums otherwise it will be deleted.ĭiscussions on illicit drug synthesis, bomb making, and other illegal activities are not allowed and will lead to a ban. (2012, December 18) Valence Electrons and the Periodic Table. If the valence shell of an element is full, such as with a noble gas, then the element does not want to gain or lose an electron.įor example, alkali metals, which all have a valency of 1, want to lose that one electron and are likely to form ionic bonds (such as in the case of NaCl, or table salt) with a Group 17 element, which has a valency of 7 and wants to gain that one electron from the alkali metal (Group 1 element) to form a stable valency of 8.įor more on valence electrons and how they're related to the periodic table, I strongly recommend this video:Ĭitations: Tyler Dewitt. They determine how "willing" the elements are to bond with each other to form new compounds. Valence electrons are responsible for the reactivity of an element. You can easily determine the number of valence electrons an atom can have by looking at its Group in the periodic table.įor example, atoms in Groups 1 and 2 have 1 and 2 valence electrons, respectively.Ītoms in Groups 13 and 18 have 3 and 8 valence electrons, respectively. Valence electrons are the electrons present in the outermost shell of an atom. To form a covalent bond, one electron from the halogen and one electron from another atom form a shared pair.įor example, in #"H–F"#, the dash represents a shared pair of valence electrons, one from #"H"# and one from #"F"#. To form an ionic bond, a halogen atom can remove an electron from another atom in order to form an anion (e.g., #"F"^"-", "Cl"^"-"#, etc.). They have one less electron configuration than a noble gas, so they require only one additional valence electron gain an octet. The most reactive nonmetals are the halogens, e.g., #"F"# and #"Cl"#. Nonmetals tend to attract additional valence electrons to form either ionic or covalent bonds. They need to lose only one or two valence electrons to form positive ions with a noble gas configuration. The most reactive metals are those from Groups 1 and 2. Generally, elements in Groups 1, 2, and 13 to 17 tend to react to form a closed shell with a noble gas electron configuration ending in #ns^2 np^6#. Elements whose atoms have the same number of valence electrons are grouped together in the Periodic Table.