Is there a certain way to find out how many bonding sites an element has? Like a formula?
If Hydrogen has an atomic mass of 7 how many bonding sites would it have? From other sites I have seen it says 7 , so are the atomic mass and bonding sites always the same or is there more to it than that?
Thanks for any help
If Hydrogen has an atomic mass of 7 how many bonding sites would it have? From other sites I have seen it says 7 , so are the atomic mass and bonding sites always the same or is there more to it than that?
Thanks for any help
-
You mean lithium, Li. Lithium has an atomic weight of 7, and has 1 valence electron. Basically, count the number of electrons you need to complete a subshell. Grab a periodic table and follow along: http://djarn.edublogs.org/files/2011/01/… For now, move He to the left so that it's right next to H. See how it's laid out as a 2-wide column, then a 10-wide column, then a 6-wide column? Those columns correspond to subshells, s, d, and p, respectively. Lithium's goal in life is to fill the subshell it finds itself in (in its case an s subshell) with electrons. (Same goes for every other element.) It already has 1 electron (count from the first element in the row to Li), it just needs 1 more (count the rest of the elements in that row of the 2-wide column). The only way it can do that is to share electrons with a second atom. The two atoms face each other, Li puts one electron into the space between them and the other atom puts one electron in, too (fair is fair, after all), and each atom feels like both electrons are somehow its own.
If you repeat this exercise with H or Na or any other element in the same column as Li, you'll get the same result. That's why elements in the same column ("group") are all so similar chemically. It won't surprise you then that in lithium hydride, LiH, lithium and hydrogen share two electrons in one chemical bond, and both are very content.
Elements in the 6-wide column, the p subshell, behave much the same way, except that they can also share the two electrons in the s subshell to make bonds, as needed. Carbon, C, lacks 4 electrons to complete the p subshell that it finds itself in, and has 4 electrons to share, 2 in the p subshell and 2 in the s subshell of the same row. It can share 1 electron with each of 4 hydrogen atoms, each of which shares 1 electron with it, to form methane CH4, with 8 pairs of electrons in 4 bonds. Each H is happy; each has 2 electrons in 1 bond to fill its s shell. The C is happy, too; it has 8 electrons in 4 bonds to fill both its s subshell (2 electrons) and its p subshell (6 electrons).
Nitrogen lacks 3 p subshell electrons. It usually forms 3 bonds to share 3 of some other atom(s)' electrons so that it can have 6 electrons for its p subshell. Ammonia, NH3, is formed this way.
This is a bit simplistic, but you'll start drawing Lewis structures soon if you haven't already, and learn more of the nuances of bonding.
q
If you repeat this exercise with H or Na or any other element in the same column as Li, you'll get the same result. That's why elements in the same column ("group") are all so similar chemically. It won't surprise you then that in lithium hydride, LiH, lithium and hydrogen share two electrons in one chemical bond, and both are very content.
Elements in the 6-wide column, the p subshell, behave much the same way, except that they can also share the two electrons in the s subshell to make bonds, as needed. Carbon, C, lacks 4 electrons to complete the p subshell that it finds itself in, and has 4 electrons to share, 2 in the p subshell and 2 in the s subshell of the same row. It can share 1 electron with each of 4 hydrogen atoms, each of which shares 1 electron with it, to form methane CH4, with 8 pairs of electrons in 4 bonds. Each H is happy; each has 2 electrons in 1 bond to fill its s shell. The C is happy, too; it has 8 electrons in 4 bonds to fill both its s subshell (2 electrons) and its p subshell (6 electrons).
Nitrogen lacks 3 p subshell electrons. It usually forms 3 bonds to share 3 of some other atom(s)' electrons so that it can have 6 electrons for its p subshell. Ammonia, NH3, is formed this way.
This is a bit simplistic, but you'll start drawing Lewis structures soon if you haven't already, and learn more of the nuances of bonding.
q
-
hydrogen is one atom with one proton, it always has an atomic mass of 1.
it can bond with as many electrons there are on its outer shell (covalently)
EG. carbon has 6 electrons, and 4 on the outer shell, so it can bond to 4 other things (e.g. hydrogens, like in methane)
one hydrogen atom can bond to one thing, like in H2O, where there are two bonds with two hydrogens, and because oxygen has 6 on its outer shell, it has 4 electrons that are not being bonded to anything (lone pairs)
it can bond with as many electrons there are on its outer shell (covalently)
EG. carbon has 6 electrons, and 4 on the outer shell, so it can bond to 4 other things (e.g. hydrogens, like in methane)
one hydrogen atom can bond to one thing, like in H2O, where there are two bonds with two hydrogens, and because oxygen has 6 on its outer shell, it has 4 electrons that are not being bonded to anything (lone pairs)