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Please help me to understand?

Please help me to understand? Topic: How to write an email examples
June 16, 2019 / By Allysdare
Question: Can someone please explain to me how to use the building-up principle to find electron configurations for the atoms of an element using the periodic table? I just cannot seem to grasp how to do it.
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Best Answers: Please help me to understand?

Terri Terri | 2 days ago
electron configuration is simply, the arrangement of electrons in an atom as you may already know. All you need to do is understand the concept of sub-shells and shells and the maximum number of electrons that can go into each energy level/shell of an atom. I'm guessing you know this, so the rest is easy. Just find the electron number. The electron number for a neutral atom is the same as the proton number and the proton number is always the atomic number. From the periodic table the atomic number is is the smaller of the two numbers which are next to the element. Say for example sodium Na in the periodic table there is 23.0 and 11. 11 is obviously the atomic number because it's the smaller of the two. The larger number is the relative atomic mass(totally irrelevant for this) Now you need to learn how the shells fill up. you might have learned that the first shell has a maximum electron of 2, the next is 8, the next is 8...the first and second are correct, but the third shell is not 8 in reality. To understand this, you need to get the concept of sub-shells. Basically, sub shells are like little apartments in each energy level/shell. In sub-shells there are orbitals, orbitals are like little rooms in the apartment(sub-shell). Orbitals can only contain 2 ELECTRONS despite what sub-shell it is only 2 electrons can fit in any orbital of any atom in chemistry. The sub-shells are: S sub-shell P sub-shell D sub-shell F sub-shell (I'm guessing you are doing As level, so F sub-shell is not relevant at this point) in the S sub-shell, there is only 1 ORBITAL remember i said 1 orbital has space for only 2 electrons, meaning that for any S sub-shell, there is only space for 2 electrons. For a P sub-shell, there are 3 orbitals, this means that the max number of electrons is 3 x 2 = 6 (because i will say again each orbital can contain only 2 electrons) For D sub-shell, there are 5 orbitals, the total number electrons would be 5 x 2 =10 The arrangements of sub-shells for the elctron configuration of atoms is like so: 1s, 2s, 2p, 3s, 3p, 4s, 3d....(here you can see why the sub-shells are going to be useful) Again with the sodium example Na atom has 11 protons and being as it is a neutral atom, it therefore has 11 electrons aswell. so the Electronic configuration would be: 1s2, 2s2, 2p6, 3s1 2+2+6+1=11 all you need to do is fill up the subshells to correspond with the elctron number. i earlier told you S has a max of 2 electron that is why you can't do something like 1s3 or 1s5 it can only be 1s2. for hydrogen, which has only 1 electron the E.C would be H = 1s1 note that i didnt put 1s2 because hydrogen has only one elctron basically to do the E.C of an atom, fill up each sub-shell, until all the electron of the atoms have entered into a subshell I know it might be a bit confusing but you can email me if you don't understand anything i wrote.
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Terri Originally Answered: Please help me to understand?
electron configuration is simply, the arrangement of electrons in an atom as you may already know. All you need to do is understand the concept of sub-shells and shells and the maximum number of electrons that can go into each energy level/shell of an atom. I'm guessing you know this, so the rest is easy. Just find the electron number. The electron number for a neutral atom is the same as the proton number and the proton number is always the atomic number. From the periodic table the atomic number is is the smaller of the two numbers which are next to the element. Say for example sodium Na in the periodic table there is 23.0 and 11. 11 is obviously the atomic number because it's the smaller of the two. The larger number is the relative atomic mass(totally irrelevant for this) Now you need to learn how the shells fill up. you might have learned that the first shell has a maximum electron of 2, the next is 8, the next is 8...the first and second are correct, but the third shell is not 8 in reality. To understand this, you need to get the concept of sub-shells. Basically, sub shells are like little apartments in each energy level/shell. In sub-shells there are orbitals, orbitals are like little rooms in the apartment(sub-shell). Orbitals can only contain 2 ELECTRONS despite what sub-shell it is only 2 electrons can fit in any orbital of any atom in chemistry. The sub-shells are: S sub-shell P sub-shell D sub-shell F sub-shell (I'm guessing you are doing As level, so F sub-shell is not relevant at this point) in the S sub-shell, there is only 1 ORBITAL remember i said 1 orbital has space for only 2 electrons, meaning that for any S sub-shell, there is only space for 2 electrons. For a P sub-shell, there are 3 orbitals, this means that the max number of electrons is 3 x 2 = 6 (because i will say again each orbital can contain only 2 electrons) For D sub-shell, there are 5 orbitals, the total number electrons would be 5 x 2 =10 The arrangements of sub-shells for the elctron configuration of atoms is like so: 1s, 2s, 2p, 3s, 3p, 4s, 3d....(here you can see why the sub-shells are going to be useful) Again with the sodium example Na atom has 11 protons and being as it is a neutral atom, it therefore has 11 electrons aswell. so the Electronic configuration would be: 1s2, 2s2, 2p6, 3s1 2+2+6+1=11 all you need to do is fill up the subshells to correspond with the elctron number. i earlier told you S has a max of 2 electron that is why you can't do something like 1s3 or 1s5 it can only be 1s2. for hydrogen, which has only 1 electron the E.C would be H = 1s1 note that i didnt put 1s2 because hydrogen has only one elctron basically to do the E.C of an atom, fill up each sub-shell, until all the electron of the atoms have entered into a subshell I know it might be a bit confusing but you can email me if you don't understand anything i wrote.

Rosaleen Rosaleen
For the lighter elements, it's easy; you just fill up the shells and subshells in order. For the heavier ones, it gets trickier; some d and f orbitals are of lower energy than the s or p orbitals of the next shell out, so those you have to look up in a table. Often, periodic tables show the electron configuration.
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Mora Mora
Electrons will be the same as the atomic number ++ protons . Like , if the atomic number was 8 , then protons ++ electrons would be 8 too . All the elements within the same group , have the same number of electrons .
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Lisha Lisha
Write out the orbitals in order of increasing energy. Start at the bottom, putting just two electrons in each separate orbital (so that 1s and 2s each get 2; 2p gets 6), and carry on until you run out of electrons. That's all! One tricky thing. 4s is just lower in energy than 3d; but in all chemical compounds of transition metals, 3d is just lower than 4s.
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Karena Karena
example: Hydrogen has one electron in the s-orbital of the first shell, so its configuration is written 1s1. Lithium has two electrons in the 1s-subshell and one in the (higher-energy) 2s-subshell, so its configuration is written 1s2 2s1 (pronounced "one-ess-two, two-ess-one"). Phosphorus (atomic number 15), is as follows: 1s2 2s2 2p6 3s2 3p3.
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Karena Originally Answered: How can I understand Geometry?
I completely understand you. There are people who are better at Algebra and those are people better at Geometry. Most people I know suck at Geometry, but are good at Algebra (like me). My dad, however, is really good at Geometry, but isn't the brightest bulb in Algebra. I took Geometry last year and I know what your going through. I looked at problems so hard and just couldn't figure them out. The only part that was a breeze, was the Pathogrean theroem and naming the type of triangle. It was very hard for me to know which theorem, postulate, proofs, etc to use for a problem. And the thing I despise about Geometry is, that when you finally understand how to do something, but then the next problem is slightly different (like lets say you have to solve for a different side and have to do a totally different process). I made a "B" on ONE test the whole semester and I did my homework everyday and I spents hours and hours of trying to study, but just couldn't do it. Continued in source-

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