Quoting Post Archived Topic: It will not be bumped to the top of the forum. Topic Can someone explain this please? (science) Membername   Not a member? Sign Up Free (takes 20 seconds) Password   Forgotten your password? Post Font: Verdana Arial Black Georgia Comic Sans Impact   Size: Tiny Normal Big Huge   Color: Default Dark Red Red Orange Brown Green Olive Cyan Blue Dark Blue Indigo Black [ Check Spelling ] [ Post Preview ] [ LiveTags ] Quote: from [m]Arcarius[/m] at 2:10 pm on Sep. 14, 2008[quote]I think it's that metals want to give away electrons and non-metals want to take them Electro negativity and ionization energy[/quote] FAQ Keyword Search: Post Options Favorites Manager Notify me of new replies to this topic by email Notify me of new replies to this topic by private message Original Post ukichik Posted at 2:07 pm on Sep. 14, 2008 I don't need you to do my homework so explain something. So we're learning compounds in class and we have to write a chemical formula when given a chemical name. I understand that but I don't understand how do you know when an electron "leaves" or "comes" to form an ion (a complete circle of 8 electrons in outer shell) Can someone explain please?

Replies MrIndigo Posted at 9:18 pm on Sep. 14, 2008 " I understand that but I don't understand how do you know when an electron "leaves" or "comes" to form an ion (a complete circle of 8 electrons in outer shell) " "a complete circle of 8 electrons in outer shell" wrong definition.. don't use that. Draw the electron configuration diagram is a much better way to determine a molecule is electron deficient or not. If a bond forms, then the electron will be close to the more ELECTRONEGATIVE element. ionic and covalent is simply made up by people to simply the bond types for beginners. Ionic bonds are when the electronegativity of the two bonding atoms are so great that the electron is just really close to the other atom. Also.. ionic atoms can dissociate:P Basically, you put the negative charge on the more electronegative atom... if they are not in the ionic range, then just put the partial negative charge on the more electronegative  atom. ukichik Posted at 2:32 pm on Sep. 14, 2008 thanks everyone even though yuo all gave different explanations :P marshmellowman Posted at 2:16 pm on Sep. 14, 2008 An element in it's normal state doesn't always have a full outer shell, in fact it rarely does. Those that do are called the halogens and are in group 8 (or 0). An element always tries to reach it's most stable state, and it can achieve this by having a full outer shell. To do this an element can either gain electrons or lose electrons. For those with less than 4 electrons in its outer shell, it is simpler and takes less energy to lose the electrons and get a full outer shell (it being the second outer shell - now the first) than it would to gain electrons and get a full outer shell. Conversely it takes less energy for elements with more than four electrons in their outer shell to gain electrons and get a full shell than it does for them to lose the electrons. Elements with exactly 4 electrons can go either way. When an element loses or accepts electrons it forms an ion, because the number of protons are not the same as the number of electrons. When it loses electrons it forms a positive charge, when it gains electrons it forms a negative charge. For example Magnesium contains 2 electrons in its outer shell (being in group 2), so it loses two electrons to form its ion - Mg2+. Chlorine however has 7 electrons in its outer shell, so it gains one electron to become the ion Cl-. icecalay Posted at 2:15 pm on Sep. 14, 2008 Okay, the groups 1, 2, and 3 will need to loose a certain number of electrons. The groups 5, 6, and 7 will need to gain electrons for a full outer shell. Get it? Just say if you need more explaination. ukichik Posted at 2:15 pm on Sep. 14, 2008 ok thanks:D:D:D Arcarius Posted at 2:12 pm on Sep. 14, 2008 Quote: from ukichik at 5:11 pm on Sep. 14, 2008 nooo i mean how do you know when if for example you need 5 electrons (because theres only 3 in the outer shell) , how do you know if you ADD 5 or SUBTARCT 3? Well non-metals take electrons, so I guess you add to them. Metals give them away so you subtract? ukichik Posted at 2:11 pm on Sep. 14, 2008 nooo i mean how do you know when if for example you need 5 electrons (because theres only 3 in the outer shell) , how do you know if you ADD 5 or SUBTARCT 3? Arcarius Posted at 2:10 pm on Sep. 14, 2008 I think it's that metals want to give away electrons and non-metals want to take them Electro negativity and ionization energy Angel Star Posted at 2:10 pm on Sep. 14, 2008 im doing the same thing in science i think that the electrons are always there cause a atom (ion) is made up of neutrons, electrons and protons. Ancient Rights Posted at 2:08 pm on Sep. 14, 2008 When an electron leaves or comes it is an ionic bond. Generally ionic bonds form between metals and nonmetal. Natsy Posted at 2:07 pm on Sep. 14, 2008 Post from this position was omitted due to content violations All 11 previous replies displayed.