![]() ![]() Using technology, however, scientists have been able to create additional elements that do not naturally occur. Roughly 90 of these elements occur naturally on Earth. You won’t see these variations listed on the Periodic Table, but the atomic mass that you see for various elements hints at these isotopes because it is an average of the most common masses for that element in nature.Īn element of any substance cannot be broken down into simpler substances by ordinary chemical processes. Atoms of the same element that have a different amount of neutrons than what is most common in nature are called isotopes. Usually, the number of neutrons in an element’s atom will be the same, but sometimes there are differences. Atoms of the same element will have the same number of protons in their nucleus. That means all of the elements that are alike will have atoms with the same structure and characteristics. On the next page, we will discuss in detail what each of these things mean.Īn element is a pure substance that is made up of only one kind of atom. These things help you tell the different elements apart from each other. Note that the periodic table above has a slightly different key, and the atomic mass is on top, next to the atomic number. This diagram shows you the key details you will need to identify when looking at an element on the Periodic Table: its atomic number, chemical symbol, chemical name, atomic mass, and some other details you won’t need to know immediately. You will see that some periodic tables will give you much more information, but, for now, we will stick to the basics. The information in this box is a little simplified. It presents an enlarged version of one of the boxes you will see on the Periodic Table. When you learn more about how the Periodic Table is organized, though, you will see that it shows you a lot of useful information about elements. At first, it seems like there’s no telling what it could all mean. It’s filled with a bunch of numbers and symbols. Then the halogens in red (s2 +p5 = 7 valence) compare to the 7 valence electrons present in manganese which is also in red.Reading the Periodic Table can seem to be very confusing at first. Calcium and Zinc both have 2 4s electrons. The same color coding trend is true for the purple. In copper the d orbitals fill up (10 electrons) then the 4s1 fills. The elements copper, gold etc (which are also light blue) also have a single s valence electron. Notice the alkali metals which only have a single s shell valence electron are light blue. The color coding seems to be really important. That's why the center of the table is expanded. The center of the table has the d-block which can have a total of 18 valence electrons. Do that again until you get to carbon and silicon which are smack in the middle. Move one column towards the center and you gain or lose an electron from the valence shell. On both sides there are full valence shells (noble gases). It looks like it's sorted by the number of valence electrons. 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. ![]()
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