The list below gives the elements arranged by increasing atomic number and shows the number of electrons per shell. There's an important distinction between "the number of electrons possible in a shell" and "the number of valence electrons possible for a period of elements". The fourth energy level of the periodic table includes the 4s 3d and 4p orbitals. Partner is not responding when their writing is needed in European project application. I'm wondering if they are distinguishable in another way (e.g., based upon which p orbital begins to acquire electrons once the s orbital in their respective shell is full). Which of the following signs of a chemical reaction are observed in the reaction of potassium with water? 2nd shell - 8 electrons. MathJax reference. p: 3 orbitals, 6 electrons. Stack Exchange network consists of 181 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. Each orbital can hold 2 electrons (one of each spin), and a maximum of 7 f orbitals can have the same energy without violating Paulis exclusion principle. Group 13: 3 electrons in highest energy level. Differences in chemical reactivity between elements are based on the number and spatial distribution of their electrons. Analytical cookies are used to understand how visitors interact with the website. Ill clearly explain this to you in just a few seconds. two filled Neon has a total of ten electrons which means two filled shells. I'm confused about all the 1s2 2s2 and 2p6. The consent submitted will only be used for data processing originating from this website. Each shell is composed of one or more subshells, which are themselves composed of atomic orbitals. Because I only have one orbital, two electrons will fill this energy level. tell how many electrons can fit into each type of subshell, s, p, d, f tell what is meant when a subshell is incompletely filled explain why electrons are commonly represented with arrows . I'm confused about what 1s and 2p and what that stuff is. How many electrons with l = 1 does Si in its ground state have? For valence shell, see, "Atomic shell" redirects here. We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. Thus, the fourth level can hold up to 32 electrons: 2 in the s orbital, 6 in the three p orbitals, 10 in the . But, they take up more space when you think about how they move. However, the M shell starts filling at sodium (element 11) but does not finish filling till copper (element 29), and the N shell is even slower: it starts filling at potassium (element 19) but does not finish filling till ytterbium (element 70). 227 , 2735]. . So the third shell can be considered to hold 8 or 18 electrons but in total the third shell can hold 18 electrons. The. The third shell can hold 32 electrons. I keep seeing this on my test and I don't know what to do. The third column is the maximum number of electrons that can be put into a subshell of that type. Budget formulation is the process of determining the, How is sheet music written? Moseley's work did not directly concern the study of electron shells, because he was trying to prove that the periodic table was not arranged by weight, but by the charge of the protons in the nucleus. The first elements to have more than 32 electrons in one shell would belong to the g-block of period 8 of the periodic table. Energy must be added to move an electron outward to a higher energy level, and energy is released when an electron falls down from a higher energy level to a closer-in one. 285-286. In this table, you can see that helium has a full valence shell, with two electrons in its first and only, 1n, shell. [1] For an explanation of why electrons exist in these shells, see electron configuration.[2]. The 3d, 4d etc., can each hold ten electrons, because they each have five orbitals, and each orbital can hold two electrons (5*2=10). Out of these, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. This is because the $3d$-orbitals aren't filled until we get to elements from the 4th period - ie. How to extract the coefficients from a long exponential expression? The first shell has 1 subshell, which has 1 orbital with 2 electrons total. Each shell can contain only a fixed number of electrons: The first shell can hold up to two electrons, the second shell can hold up to eight (2 + 6) electrons, the third shell can hold up to 18 (2 + 6 + 10) and so on. Stud.Hist.Set.,No. 4, p. 740. Elements are placed in order on the periodic table based on their atomic number, how many protons they have. When. rev2023.3.1.43269. Within the shells, electrons are further grouped into subshells of four different types, identified as s, p, d, and f in order of increasing energy. The existence of electron shells was first observed experimentally in Charles Barkla's and Henry Moseley's X-ray absorption studies. The second shell can hold 8 electrons. The general formula is that the nth shell can in principle hold up to 2(n 2) electrons. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. I'll try to explain with the help of an example. The elements past 108 have such short half-lives that their electron configurations have not yet been measured, and so predictions have been inserted instead. It consists of the 2s and 2p shells. This shell can contain a maximum of two electrons. The filling of the shells and subshells with electrons proceeds from subshells of lower energy to subshells of higher energy. Z. Kristallogr. The general formula is that the nth shell can in principle hold up to 2(n2) electrons. Chemistry Electron Configuration s,p,d,f Orbitals 1 Answer Junaid Mirza May 9, 2018 2,6,10,14 respectively Explanation: If is the angular quantum number of subshell then maximum electrons it can hold is 2(2 +1) Sub-shellMaximum electrons How many shells are in F? Most of it is based on theory worked out using a lot of maths. NOTE the pattern of an increase of 4 additional . Hist. Quantum: Einstein, Bohr, and the great debate about the nature of reality / Manjit Kumar.1st American ed., 2008. Now, if you want to know the electron configuration of all these elements, then see the below Periodic table. Does the third shell have 8 or 18 electrons? Making statements based on opinion; back them up with references or personal experience. The 2p, 3p, 4p, etc., can each hold six electrons because they each have three orbitals, that can hold two electrons each (3*2=6). So far, scientists haven't discovered any elements that use more orbitals than this. This means that the 1s, 2s, 3s, 4s, etc., can each hold two electrons because they each have only one orbital. What are the energy shells (K, L, M, N, etc)? . Similarly, neon has a complete outer 2n shell containing eight electrons. To view the purposes they believe they have legitimate interest for, or to object to this data processing use the vendor list link below. For example, the "4s subshell" is a subshell of the fourth (N) shell, with the type (s) described in the first row. 3). But what about after that? S sub-shells only have one orbital, p sub-shells have three, and the d sub-shell has five. The final column gives the historical origin of the labels s, p, d, and f. They come from early studies of, Each s subshell holds at most 2 electrons, Each p subshell holds at most 6 electrons, Each d subshell holds at most 10 electrons, Each f subshell holds at most 14 electrons, Each g subshell holds at most 18 electrons, This page was last edited on 30 November 2022, at 19:37. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. An easy way to visualize this is like this: The pattern of maximum possible electrons = $2n^2$ is correct. Thus, option c is correct. How many electrons are required to fill and orbital? As shown in Figure 1, there are at least seven shells available to the electrons in any atom. It has: An s-orbital holds 2 electrons. Posted 8 years ago. The subshells s, p, d, and f contain the following number of orbitals respectively, where every orbital can hold up to two electrons maximum: s: 1 orbital, 2 electrons. Each successive shell can only hold a certain number of electrons. First, we look at the n=1 shell (the first shell). The values of $m_\ell$ are integers and depend on the value of $\ell$: $m_\ell = -\ell,,-1,0,1,,+\ell$, $m_s$, the spin angular momentum quantum number defines the spin state of each electron. What are examples of software that may be seriously affected by a time jump? How many electrons can fit in each shell? This would mean 2 electrons could fit in the first shell, 8 could fit in the second shell, 18 in the third shell, and 32 in the fourth shell. How are atomic orbitals filled with electrons? Group 2: 2 electrons in highest energy level. When the modern quantum mechanics theory was put forward based on Heisenberg's matrix mechanics and Schrdinger's wave equation, these quantum numbers were kept in the current quantum theory but were changed to n being the principal quantum number, and m being the magnetic quantum number. What is the formula for calculating solute potential? "he third electron shell, 3n, also contains an ssss orbital and three pppp orbitals, and the third-row elements of the periodic table place their electrons in these orbitals, much as second-row elements do for the 2n shell. There are three 2p orbitals, and they are at right angles to each other. [4][12] The origin of this terminology was alphabetic. Chap.7. As work continued on the electron shell structure of the Sommerfeld-Bohr Model, Sommerfeld had introduced three "quantum numbers n, k, and m, that described the size of the orbit, the shape of the orbit, and the direction in which the orbit was pointing. Each shell can contain only a fixed number of electrons: the first shell can hold up to two electrons, the second shell can hold up to eight (2 + 6) electrons, the third shell can hold up to 18 (2 + 6 + 10) and so on. The first shell is filled with 2 electrons, the second is filled with 8 electrons, and the third is filled with 8. Because in Bohrs model for hydrogen atom we consider only Coulombic interactions between one proton and one electron. 1). "Langmuir's Theory of the Arrangement of Electrons in Atoms and Molecules". The orbital shapes start to get weird after that. By convention, each shell is assigned a number and the symbol nfor example, the electron shell closest to the nucleus is called 1n. How many electrons fill each energy level and each orbital? The electrons revolve around the nucleus in the specific paths which are known as orbits or shells. Which of these two methods is correct and should be used to find the number of electrons in an orbital? (ed.) 2n2 is the maximum number of electrons in each shell where 'n' is the number of the shell. Each shell can contain only a fixed number of electrons, up to two electrons can hold the first shell, up to eight (2 + 6) electrons can hold the second shell, up to 18 (2 + 6 + 10) can hold the third shell and so on. doi:10.1021/ja01440a023. the f type has seven orbitals Each orbital can hold up to two electrons, meaning that the 1s, 2s, 3s, 4s, and 5s can hold two electrons. 3, no. The general formula is that the n th shell can in principle hold up to 2 ( n2) electrons. The $s$ subshell has one orbital for a total of 2 electrons, The $p$ subshell has three orbitals for a total of 6 electrons, The $d$ subshell has five orbitals for a total of 10 electrons, The $f$ subshell has seven orbitals for a total of 14 electrons, The $g$ subshell has nine orbitals for a total of 18 electrons, The $h$ subshell has eleven orbitals for a total of 22 electrons, The first shell only has the $s$ subshell $\implies$ 2 electrons, The second shell has the $s$ and $p$ subshells $\implies$ 2 + 6 = 8 electrons, The third shell has the $s$, $p$, and $d$ subshells $\implies$ 2 + 6 + 10 = 18 electrons, The fourth shell has the $s$, $p$, $d$, and $f$ subshells $\implies$ 2 + 6 + 10 + 14 = 32 electrons, The fifth shell has the $s$, $p$, $d$, $f$, and $g$ subshells $\implies$ 2 + 6 + 10 + 14 + 18 = 50 electrons, The sixth shell has the $s$, $p$, $d$, $f$, $g$, and $h$ subshells $\implies$ 2 + 6 + 10 + 14 + 18 + 22 = 72 electrons, $n$, the principle quantum number defines the shell. Now for the different kinds of orbitals Each shell consists of one or more subshells, and each subshell consists of one or more atomic orbitals. However, the outcome is the following: Each energy level (shell) has more subshells available to it: The pattern is thus: $2, 8, 18, 32, 50, 72, $ or $2n^2$. In addition, how many electrons can each shell store? And, they also move fast and they act like gas particles, in a way. We also use third-party cookies that help us analyze and understand how you use this website. Kragh, Helge. Observing the diagram, we can observe that the second shell of an atom can hold 12 electrons, If the spin quantum number m s could have 3 values instead of just 2. Browse other questions tagged, Start here for a quick overview of the site, Detailed answers to any questions you might have, Discuss the workings and policies of this site. Michael Eckert, Disputed discovery: the beginnings of X-ray diffraction in crystals in 1912 and its repercussions, January 2011, Acta crystallographica. 32 Regardless of shape, each orbital can hold up to two electrons. A useful guide when understanding electron shells in atoms is to note that each row on the conventional periodic table of elements represents an electron shell. Experimental observations, such as the energy released or absorbed when electrons move from one state to another, corroborate the theory. https://www.aip.org/history-programs/niels-bohr-library/oral-histories/4517-3, "XXXIX.The spectra of the fluorescent Rntgen radiations", "Quantum Mechanic Basic to Biophysical Methods", Electron configurations of the elements (data page), https://en.wikipedia.org/w/index.php?title=Electron_shell&oldid=1124837255, Wikipedia indefinitely semi-protected pages, Creative Commons Attribution-ShareAlike License 3.0. Other than quotes and umlaut, does " mean anything special? In chemistry and atomic physics, an electron shell may be thought of as an orbit followed by electrons around an atom's nucleus. Atoms, like other things governed by the laws of physics, tend to take on the lowest-energy, most stable configuration they can. Direct link to Sebastian Castro's post If the Bohr model is an i, Posted 4 years ago. There is a 2 8 8 rule for these elements. Do atoms react to fill outer shell or 8 valence electrons? Each shell can contain only a fixed number of electrons: the first shell can hold up to two electrons, the second shell can hold up to eight (2 + 6) electrons, the third shell can hold up to 18 (2 + 6 + 10) and so on. Here is a table showing electrons in each shell. Each shell can contain only a fixed number of electrons: The first shell can hold up to two electrons, the second shell can hold up to eight (2 + 6) electrons, the third shell can hold up to 18 (2 + 6 + 10) and so on. If the Bohr model is an inaccurate representation of electron's movement, why is it so universally accepted? The fourth column says which shells have a subshell of that type. How many electrons can be accommodated in each shell? The number of electrons in the outermost shell of a particular atom determines its reactivity, or tendency to form chemical bonds with other atoms. Thanks, I am not sure where the confusion is. Connect and share knowledge within a single location that is structured and easy to search. Because of this, the later shells are filled over vast sections of the periodic table. It has the 2s and 2p subshells. The K shell fills in the first period (hydrogen and helium), while the L shell fills in the second (lithium to neon). These patterns do not fill the outermost shell or satisfy the octet rule, making chlorine and sodium reactive, eager to gain or lose electrons to reach a more stable configuration. In general, the number of valence electrons is the same within a column and increases from left to right within a row. 3(1964),6-28. Number of electrons in each shell.Orbit / Shell (n)Maximum no. How many electrons does the first shell of a Bohr model hold? The names of the electron shell were given by a spectroscopist named Charles G Barkla. The shells correspond to the principal quantum numbers (n = 1, 2, 3, 4) or are labeled alphabetically with the letters used in X-ray notation (K, L, M,). The innermost shell is filled first. In. Thus the $s$ subshell has only 1 orbital. The third shell has 3 subshells: the $s$ subshell, which has 1 orbital with 2 electrons, the $p$ subshell, which has 3 orbitals with 6 electrons, and the $d$ subshell, which has 5 orbitals with 10 electrons, for a total of 9 orbitals and 18 electrons. The $p$ subshell has dumbbell-shaped orbitals. An early model of the atom was developed in 1913 by the Danish scientist Niels Bohr (18851962). If we consider just the first three rows of the table, which include the major elements important to life, each row corresponds to the filling of a different electron shell: helium and hydrogen place their electrons in the 1n shell, while second-row elements like Li start filling the 2n shell, and third-row elements like Na continue with the 3n shell. Press ESC to cancel. Use MathJax to format equations. 2 x 3 = 6 electrons in Subshell-p 2 x 5 = 10 electrons in Subshell-d 2 x 7 = 14 electrons in Subshell-f That makes the full shells, the 2 (hemispheres) by PI*r-squared interlaced (with hemispheres and 2nd layers offset by 1/2 phase), so Shell-1: 1 x 2 = 2 electrons Shell-2 / -3: (1+3) = 4 x 2 = 8 electrons Element . Schilpp, Paul A. The cookies is used to store the user consent for the cookies in the category "Necessary". Manage Settings How much can SPDF hold? It's hard for me to understand, I was wondering if you could help out with that? Re: Why do electron shells have set limits? How to Market Your Business with Webinars. To log in and use all the features of Khan Academy, please enable JavaScript in your browser. Charles G. Barkla M.A. 4th shell can hold 32 electrons. Why are electron configurations more stable when there are 8 electrons in the outer shell? List of elements with electrons per shell, (For Interactive Periodic table, view on laptop/desktop for better experience. How many electrons are in 1 shell? . How many electrons can a F-type shell hold? s-orbitals can hold 2 electrons, the p-orbitals can hold 6 electrons. atoms Share Improve this question Follow edited Nov 9, 2019 at 19:12 A.K. Each shell (or energy level) has some number of subshells, which describe the types of atomic orbitals available to electrons in that subshell. These letters were later found to correspond to the n values 1, 2, 3, etc. Ask Question Asked 9 years, 1 month ago Modified 3 years, 3 months ago Viewed 16k times 1 I know that the first shell can hold up to 2, the second and third can hold up to 8, and the fourth 18. The 3n is the third electron shell, and it also consists of 3s and 3p shells. The maximum number of electrons that the K, L, M, and N shells of an atom can hold is 2, 8, 18, and 32, respectively. Chemistry Stack Exchange is a question and answer site for scientists, academics, teachers, and students in the field of chemistry. VII in the series The Library of Living Philosophers by Open Court, La Salle, IL, Einstein, Albert 'Autobiographical Notes', pp.45-47. Acceleration without force in rotational motion? The 3n shell also contains a dddd orbital, but this orbital is considerably higher in energy than the 3s3s3s3, s and 3p3p3p3, p orbitals and does not begin to fill until the fourth row of the periodic table. Direct link to Sean Cozart's post How do scientists figure , Posted 5 years ago. Thus, to find the number of electrons possible per shell. To learn more, see our tips on writing great answers. As for "how many shells the atom has," I already said that it has an infinite number of empty ones. Kumar, Manjit. Some atoms can be stable with an octet even though their valence shell is the 3n shell, which can hold up to 18 electrons. Do scientists Figure, Posted 4 years ago get weird after that the lowest-energy, most configuration... Third shell have 8 or 18 electrons an early model of the Arrangement of electrons scientists Figure Posted! Enable JavaScript in your browser determining the, how is sheet music written in one shell would belong the... Governed by the Danish scientist Niels Bohr ( 18851962 ) take up more space when you about! And 3p shells is it so universally accepted Langmuir 's theory of the periodic table of 3s 3p... Each other which means two filled shells thanks, i was wondering if you want know... Students in the specific paths which are known as orbits how many electrons can each shell hold shells that use more orbitals than this shells. Known as orbits or shells 's and Henry Moseley 's X-ray absorption studies they move to 2 ( n maximum. It so universally accepted with water and one electron experience by remembering your preferences and repeat visits representation of 's... Were given by a time jump the 3n is the process of determining the, how is music! Subshells, which are themselves composed of atomic orbitals the confusion is here is a table showing electrons in energy! Between one proton and one electron electrons that can be considered to hold 8 or 18 electrons my test i... Answer site for scientists, academics, teachers, and the third column is same! Of why electrons exist in these shells, see our tips on writing great answers, most stable they... Is a 2 8 8 rule for these elements or personal experience shell is filled 8. Electrons but in total the third electron shell, see our tips on writing great answers electrons does third! Inc ; user contributions licensed under CC BY-SA weird after that eight electrons 8 rule for these elements a of... Category `` Necessary '' Regardless of shape, each orbital can hold 2 electrons total 's how..., view on laptop/desktop for better experience electrons fill each energy level the, how many electrons the... 2 8 8 rule for these elements, then see the below table. Is the same within a single location that is structured and easy to search third-party cookies help! ) electrons the same within a column and increases from left to right within a and. Of lower energy to subshells of higher energy of higher energy how many electrons can each shell hold, 3, etc ) your... Ground state have have a subshell of that type shells was first experimentally. To store the user consent for the cookies in the field of.... Than quotes and umlaut, does `` mean anything special / Manjit Kumar.1st American ed.,.! Configuration. [ 2 ] eight electrons electrons total Follow edited Nov 9, at... To the n values 1, there are at right angles to each other in European project application Niels (! For scientists, academics, teachers, and students in the specific paths which are themselves of! List of elements with electrons proceeds from subshells of higher energy universally accepted of their electrons exist in these,! In Figure 1, there are 8 electrons, the p-orbitals can hold 18?. There are three 2p orbitals, and students in the specific paths which are themselves composed of one or subshells! The field of chemistry use more orbitals than this of electrons possible per shell to fill outer shell what and! Electrons in one shell would belong to the n th shell can only hold a certain number electrons!. [ 2 ] at the n=1 shell ( n ) maximum.. To store the user consent for the cookies in the field of chemistry Kumar.1st American ed., 2008 only. Signs of a chemical reaction are observed in the field of chemistry n=1 shell ( the first shell a... Observations, such as the energy shells ( K, l, M, n, etc another corroborate... There is a table showing electrons in any atom software that may be thought of as an orbit how many electrons can each shell hold electrons! That is structured and easy to search elements from the 4th period - ie filling! Of reality / Manjit Kumar.1st American ed., 2008 that type, please JavaScript... Us analyze and understand how you use this website this website given by a spectroscopist named Charles Barkla! Stable configuration they can the 1s2 2s2 and 2p6 the fourth energy level this energy level each. Is it so universally accepted can contain a maximum of two electrons will fill this energy level to hold or... User contributions licensed under CC BY-SA would belong to the electrons in highest energy level of the atom was in! Electrons that can be put into a subshell of that type the user consent the... 8 or 18 electrons but in total the third shell can contain a maximum of two.. The features of Khan Academy, please enable JavaScript in your browser ; contributions! Lowest-Energy, most stable configuration they can number, how many electrons can be accommodated in shell.Orbit. 3, etc 9, 2019 at 19:12 A.K do n't know what to do absorption studies by Danish! And increases from left to right within a column and increases from to! Are three 2p orbitals, and the d sub-shell has five most stable configuration they can electrons around atom. Of why electrons exist in these shells, see our tips on writing great answers configurations more stable there. 12 ] the origin of this terminology was alphabetic is a question and answer site scientists. N'T filled until we get to elements from the 4th period - ie used for data processing from! An easy way to visualize this is because the $ s $ subshell has only orbital... Start to get weird after that correct and should be used to find the number of electrons that be! See electron configuration of all these elements reaction are observed in the reaction of potassium with?. January 2011, Acta crystallographica, etc formulation is the maximum number of electrons in highest level. $ 3d $ -orbitals are n't filled until we get to elements from the 4th period ie. Lot of maths, there are three 2p orbitals, and they act like gas particles, in a.... For an explanation of why electrons exist in these shells, see, `` atomic shell '' redirects.. A complete outer 2n shell containing eight electrons which means two filled Neon has total. N 2 ) electrons d sub-shell has five music written table based on ;... How to extract the coefficients from a long exponential expression not responding when their writing is needed European... Neon has a total of ten electrons which means two filled shells relevant experience by remembering your and... Complete outer 2n shell containing eight electrons category `` Necessary '' sections of the atom was developed in 1913 the. Are three 2p orbitals, and it also consists of 3s and 3p shells the most relevant experience remembering... The features of Khan Academy, please enable JavaScript in your browser shell.... Space when you think about how they move up with references or personal experience methods correct. 9, 2019 at 19:12 A.K statements based on opinion ; back them up with references or personal experience 2. Eight electrons elements with electrons proceeds from subshells of lower energy to subshells of lower energy subshells... Between one proton and one electron of X-ray diffraction in crystals in 1912 and repercussions... Thought of as an orbit followed by electrons around an atom 's nucleus worked out using a lot of.! Will only be used for data processing originating from this website letters were later found to correspond the., Neon has a complete outer 2n shell containing eight electrons direct link to Sebastian Castro 's if! And one electron want to know the electron shell may be thought of as orbit. Each successive shell can contain a maximum of two electrons electrons, p-orbitals. More subshells, which has 1 subshell, which are known as orbits or shells at 19:12 A.K increase. A total of ten electrons which means two filled shells with references or personal experience laptop/desktop for better.! Is used to store the user consent for the cookies in the category `` Necessary '' the same a..., academics, teachers, and students in the specific paths which are known orbits! Exponential expression our website to give you the most relevant experience by remembering your preferences and repeat visits Niels... Of electrons we get to elements from the 4th period - ie you could help with... You the most relevant experience by remembering your preferences and repeat visits how use. Of that type exponential expression under CC BY-SA filled over vast sections of the periodic table, view on for... Model of the shells and subshells with electrons per shell on theory out. And 2p6 this: the pattern of an example is filled with 8 electrons each. The nature of reality / Manjit Kumar.1st American ed., 2008 easy way to visualize this is because $. That is structured and easy to search or shells ( for Interactive periodic table based on their atomic and... Below gives the elements arranged by increasing atomic number and spatial distribution of their electrons hold. Experimental observations, such as the energy released or absorbed when electrons from! Of higher energy the list below gives the elements arranged by increasing atomic number, how many electrons required... Eckert, Disputed discovery: the beginnings of X-ray diffraction in crystals in 1912 its. Number and shows the number and shows the number and shows the number of electrons in one shell would to. Hold 2 electrons total chemistry and atomic physics, an electron shell given... Of potassium with water because i only have one orbital, two electrons / Manjit Kumar.1st ed.. Configuration of all these elements first elements to have more than 32 electrons in highest energy level two is... I do n't know what to do 8 or 18 electrons but in total the third is. 13: 3 electrons in any atom knowledge within a row or shells this is because the s!