Part 2.3 How to work out the electron configurations of atoms for elements of atomic numbers Z = 1 to 58 and the derived electron arrangement of selected 'simple' ions

Parts 2.1 to 2.2 should be read and studied first!

Sub-index for three sections on this page and other sections on separate pages

Part 2.3 uses the rules on assigning electron arrangements, and how the quantum level notation is written out, and using boxes to represent orbitals, as well as the usual written orbital notation, is given for elements Z = 1 to 56.

Part 2.4 The relationship between electron configuration and the Periodic Table and uses the electron configurations to show how the Periodic Table arises, i.e. an element's position in the Periodic Table and hence its chemistry, is primarily determined by the arrangement of its outer valency electrons.

Part 2.5 shows how to work out the electron configuration of ions, (positive cations or negative anions formed by the loss or gain of valence electrons) and relating electron arrangements to the oxidation states exhibited by selected elements.

See also on other separate pages part ...

2.1 The electronic basis of the modern Periodic Table

2.2 The electronic structure of atoms (including s p d f subshells/orbitals/notation) 

2.6 Spectroscopy and the hydrogen spectrum

2.7 Evidence of quantum levels from ionisation energies

2.8 Emission and absorption spectra of elements

The electron configuration of all 118 elements laid out in the Periodic Table

 2.3 List of the Electron Configurations of Elements Z = 1 to 56 using the advanced s, p, d and f notation

YOU MUST STUDY Parts 2.1 and 2.2 before studying section 2.3 onwards – The rules of how to assign electrons in multi–electron atoms to the appropriate quantum levels were explained in section 2.2.

The list below quotes the ground state electron configurations i.e. the lowest available state according to the Aufbau principle (previously described). The order of filling the electron levels is listed below and also indicated on the diagram below.

Electron Box diagrams of the outer electron arrangement and examples of the simple electron notation (e.g. 2.8.1) are also included, with brief comments in the end right hand column e.g. element symbol, group, series etc.

The electrons–in–boxes notation for subshells: Boxes are used to represent an individual orbital or set of orbitals in the electrons are shown as arrows. The pairs up/down arrows represent a full orbital with electrons of opposite spin and note how the half–filled boxes/orbitals illustrate Hund's rule of maximum multiplicity.

Energy level filling order to Z = 56 is 1s 2s 2p 3s 3p 4s 3d 4p (for Z = 1 to 36) then 5s 4d 5p 6s 4f/5d varies (for Z = 37 to 56)

However, when writing out the electron configuration you must write them out in order of strict principal quantum with the accompanying s, p, d, f notation

order of writing out is: 1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 5d 6s (up to Z = 58)

BUT the order of orbital filling is: 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s (up to Z = 56)

So at Z = 21 Sc, you start to fill the 3d orbitals (NOT 4p orbitals),

then at Z = 31 Ga you start to fill the 4p orbitals, and this is all you need pre-university! I think?

Atomic number Z element name and chemical symbol	Electron configuration i.e electron arrangement in terms of s, p, d and f notation with electron number superscripts	Electron spin box diagrams of the outer electron orbitals for electrons beyond the inner noble gas core [He/Ne/Ar/Kr], the latter are not involved in chemical bonding or reactions.	Symbol, group/series/block and Comments Gp = Group
1 Hydrogen, H	1s1	1s	H, no Group really, a bit unique!
2 Helium, He	1s2 = [He]	1s very stable, unreactive, filled shell	He, Group 0/18 Noble Gas
3 Lithium, Li	1s22s1 (simple notation: 2.1)	[He] 2s 2p  empty 2p sub-shell	Li, s–block, Gp1 Alkali Metal, v. reactive
4 Beryllium, Be	1s22s2 (2.2)	[He] 2s 2p  empty 2p sub-shell	Be, s–block, Gp2 Alkaline Earth Metal,
5 Boron, B	1s22s22p1 (2.3)	[He] 2s 2p 1st p electron	B, p–block, Group 3/13
6 Carbon, C	1s22s22p2 (2.4)	[He] 2s 2p	C, p–block, Group 4/14
7 Nitrogen, N	1s22s22p3 (2.5)	[He] 2s 2p	N, p–block, Group 5/15
8 Oxygen, O	1s22s22p4 (2.6)	[He] 2s 2p	O, p–block, Group 6/16
9 Fluorine, F	1s22s22p5 (2.7)	[He] 2s 2p	F, p–block, Group 7/17 Halogen
10 Neon, Ne	1s22s22p6  = [Ne] (2.8)	[He] 2s 2p	Ne, p–block, Group 0/18 Noble Gas - very stable, unreactive, filled outer shell
11 Sodium, Na	1s22s22p63s1 (2.8.1)	[Ne] 3s 3p empty sub-shell	Na, Gp1 Alkali Metal, v. reactive
12 Magnesium, Mg	1s22s22p63s2 (2.8.2)	[Ne] 3s 3p empty sub-shell	Mg, s–block, Gp2 Alkaline Earth Metal,
13 Aluminium, Al	1s22s22p63s23p1 (2.8.3)	[Ne] 3s 3p	Al, p–block, Group 3/13
14 Silicon, Si	1s22s22p63s23p2 (2.8.4)	[Ne] 3s 3p	Si, p–block, Group 4/14
15 Phosphorus, P	1s22s22p63s23p3 (2.8.5)	[Ne] 3s 3p	P, p–block, Group 5/15
16 Sulfur, S	1s22s22p63s23p4 (2.8.6)	[Ne] 3s 3p	S, p–block, Group 6/16
17 Chlorine, Cl	1s22s22p63s23p5 (2.8.7)	[Ne] 3s 3p	Cl, p–block, Group 7/17 Halogen
18 Argon, Ar	1s22s22p63s23p6 = [Ar] (2.8.8)	[Ne] 3s 3p	Ar, p–block, Group 0/18 Noble Gas - very stable, unreactive, filled outer shell
19 Potassium, K	1s22s22p63s23p64s1 (2.8.8.1)	[Ar] 3d 4s 4p	K, s–block, Gp1 Alkali Metal, v. reactive
20 Calcium, Ca	1s22s22p63s23p64s2 (2.8.8.1)	[Ar] 3d 4s 4p	Ca, s–block, Gp2 Alkaline Earth Metal
21 Scandium, Sc	1s22s22p63s23p63d14s2	[Ar] 3d 4s 4p	Sc, 3d block, not a true Transition Metal
22 Titanium, Ti	1s22s22p63s23p63d24s2	[Ar]3d 4s 4p	Ti, 3d block, a true Transition Metal
23 Vanadium, V	1s22s22p63s23p63d34s2	[Ar]3d 4s 4p	V, 3d block, a true Transition Metal
24 Chromium, Cr	1s22s22p63s23p63d54s1	[Ar] 3d 4s 4p	Cr, 3d block, a true Transition Metal
25 Manganese, Mn	1s22s22p63s23p63d54s2	[Ar] 3d 4s 4p	Mn, 3d block, a true Transition Metal
26 Iron, Fe	1s22s22p63s23p63d64s2	[Ar] 3d 4s 4p	Fe, 3d block, a true Transition Metal
27 Cobalt, Co	1s22s22p63s23p63d74s2	[Ar] 3d 4s 4p	Co, 3d block, a true Transition Metal
28 Nickel, Ni	1s22s22p63s23p63d84s2	[Ar] 3d 4s 4p	Ni, 3d block, a true Transition Metal
29 Copper, Cu	1s22s22p63s23p63d104s1	[Ar] 3d 4s 4p	Cu, 3d block, a true Transition Metal
30 Zinc, Zn	1s22s22p63s23p63d104s2	[Ar] 3d 4s 4p	Zn, 3d block, not a true Transition Metal
31 Gallium, Ga	[Ar]3d104s24p1	[Ar] 3d 4s 4p	Ga, p–block, Group 3/13
32 Germanium, Ge	[Ar]3d104s24p2	[Ar] 3d 4s 4p	Ge, p–block, Group 4/14
33 Arsenic, As	[Ar]3d104s24p3	[Ar] 3d 4s 4p	As, p–block, Group 5/15
34 Selenium, Se	[Ar]3d104s24p4	[Ar] 3d 4s 4p	Se, p–block, Group 6/16
35 Bromine, Br	[Ar]3d104s24p5	[Ar] 3d 4s 4p	Br, p–block, Group 7/17 Halogen
36 Krypton, Kr	[Ar]3d104s24p6 = [Kr] (2.8.18.8)	[Ar] 3d 4s4p very stable, filled outer shell	Kr, p–block, Group 0/18 Noble Gas
37 Rubidium, Rb	[Kr]5s1	[Kr] 5s	Rb, s–block, Gp1 Alkali Metal, v. reactive
38 Strontium, Sr	[Kr]5s2	[Kr] 5s	Sr, s–block, Gp2 Alkaline Earth Metal,
39 Yttrium, Y	[Kr]4d15s2	[Kr] 4d 5s	Y, 4d block, not a true Transition Metal
40 Zirconium, Zr	[Kr]4d25s2	[Kr] 4d 5s	Zr, 4d block, a true Transition Metal
41 Niobium, Nb	[Kr]4d45s1	[Kr] 4d 5s	Nb, 4d block, a true Transition Metal
42 Molybdenum, Mo	[Kr]4d55s1	[Kr] 4d 5s	Mo, 4d block, a true Transition Metal
43 Technetium, Tc	[Kr]4d55s2	[Kr] 4d 5s	Tc, 4d block, a true Transition Metal
44 Ruthenium, Ru	[Kr]4d75s1	[Kr] 4d 5s	Ru, 4d block, a true Transition Metal
45 Rhodium, Rh	[Kr]4d85s1	[Kr] 4d 5s	Rh, 4d block, a true Transition Metal
46 Palladium, Pd	[Kr]4d10	[Kr] 4d 5s	Pd, 4d block, a true Transition Metal
47 Silver, Ag	[Kr]4d105s1	[Kr] 4d 5s 5p	Ag, 4d block, a true Transition Metal
48 Cadmium, Cd	[Kr]4d105s2	[Kr] 4d 5s 5p	Cd, 4d block, not a true Transition Metal
49 Indium, In	[Kr]4d105s25p1	[Kr] 4d 5s 5p	In, p–block, Group 3/13
50 Tin, Sn	[Kr]4d105s25p2	[Kr] 4d 5s 5p	Sn, p–block, Group 4/14
51 Antimony, Sb	[Kr]4d105s25p3	[Kr] 4d 5s 5p	Sb, p–block, Group 5/14
52 Tellurium, Te	[Kr]4d105s25p4	[Kr] 4d 5s 5p	Te, p–block, Group 6/16
53 Iodine, I	[Kr]4d105s25p5	[Kr] 4d 5s 5p	I, p–block, Group7/17 Halogen
54 Xenon, Xe	[Kr]4d105s25p6 = [Xe]	[Kr] 4d 5s 5p	Xe, p–block, Group 0/8/18 Noble Gas - very stable, filled outer shell
55 Caesium, Cs	[Xe]6s1	[Xe] 6s	Cs, s–block, Gp1 Alkali Metal, very reactive
56 Barium, Ba	[Xe]6s2	[Xe] 6s	Ba, s–block, Gp2 Alkaline Earth Metal,
57 Lanthanum, La	[Xe]5d16s2	[Xe] 5d 6s	La, start of 5d–bock
58 Cerium, Ce	[Xe]4f26s2 not 4f15d16s2	things get a bit less systematic in the f blocks	Ce, 1st of f–block in the Lanthanides Metals
		A few more selected elements
81Tl Thallium	[Xe] 4f145d106s26p1	p–block, Group 3/13
82Pb Lead	[Xe] 4f145d106s26p2	p–block, Group 4/14
83Bi Bismuth	[Xe] 4f145d106s26p3	p–block, Group 5/15
84Po Polonium	[Xe] 4f145d106s26p4	p–block, Group 6/16
85At Astatine	[Xe] 4f145d106s26p5	p–block, Group 7/17 Halogen
86Rn Radon	[Xe] 4f145d106s26p6	p–block, Group 0/8/18 Noble Gas
87Fr Francium	[Rn]7s1	Group1 Alkali Metal, extremely reactive and radioactive
88Ra Radium	[Rn]7s2	Gp2 Alkaline Earth Metal, extremely reactive and radioactive

Quantum sub-shell filling order: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s

The electron spin box diagrams can be used to show the full electronic structure based on the above 'blank' set of electronic energy levels e.g.

The electron configurations of carbon and neon

The electron configurations of silicon and argon

The electron configurations of calcium and vanadium

More 'quantum level quirks'!

A note on two anomalies in the 3d block, namely the transition metals chromium and copper:

Cr is [Ar]3d⁵4s¹ and not [Ar]3d⁴4s²

and Cu is[Ar]3d¹⁰4s¹ and not [Ar]3d⁹4s²

because an inner half–filled 3d sub-shell or fully–filled 3d sub–shell orbitals seem to be a little lower in energy level, and marginally more stable.

TOP OF PAGE and INDEXES

 2.4 Electron configuration and the Periodic Table

Not all the elements are shown but the position of s, p, d and f blocks are shown and explained after the table

It is an element's electron configuration that determines whether it is an s, p, d or f block element.

Instead of 'simply' assigning an element to its group or series because of its chemical properties e.g. formula of similar compounds, we can now assign an element's position in the periodic table using its electron configuration.

An s block element has one or two outer electrons i.e. ... s¹ or ... s²  e.g. group 1 and group 2 metals (shown below)

A p block element has 1-6 outer p electrons beyond the s² orbital i.e. ... s²p¹ to s²p⁶  e.g. group 3/13 across to group 0/18 (shown below)

A d block element has 1 to 10 electrons in the outermost set of d orbitals i.e. ...d¹ to ...d¹⁰  e.g. 3d block of Sc to Zn, 4d block Y to Cd (shown below)

Note that a true transition element has an ion with an incomplete d sub-shell (3d, 4d etc.)

An f block element has 1 to 14 electrons in the outermost set of f orbitals i.e. ...f¹ to ...f¹⁴  e.g.  Ce to Lu (NOT shown below)

This partial periodic table relates an element's electron configuration to the element's position in the periodic table.

You can then see the patterns between an atom's electron arrangement and the group, block or series the element belongs to.

Electron configurations. of all elements except 4d, 5d, 5f and 6d blocks

Electron configurations. of all elements laid out in the modern full periodic table

(These two pages need a wide screen resolution to be seen in full)

• Note on Group numbers and groups, blocks and series

  • Using 0 to denote the Group number of Noble Gases is very historic now since compounds of xenon known exhibiting a valency of 8.

  • Because of the horizontal series of elements e.g. like the Sc to Zn block (10 elements), Groups 3 to 0/8 can also be numbered as Groups 13 to 18 to fit in with the actual number of vertical columns of elements and this is the modern trend in periodic table notation.

  • This can make things confusing, but there it is, classification is still in progress!

  • The atomic/proton number, decides which element an atom is and the outer electron structure decides which group/block/series the element belongs to and ultimately its chemistry.

  • The positions of the s, p and d blocks are indicated in the Periodic Table images and arise from the quantum rules for electron configurations.

  • s block elements have an outer shell of just 1 or 2 s electrons i.e. s¹ or s² configuration beyond an inner noble gas configuration (2 per period from period 2 onwards), that is groups 1 and 2. Technically, hydrogen and helium are in the s block, but bare little chemical similarity with the group 1 and group 2 metals.

    • The s block elements form the two vertical columns of the periodic table.

  • p block elements have an outer electron configuration of s²p¹ to s²p⁶ i.e. elements where the p sub-shell is being filled (6 per period from period 2 onwards), that is groups 3/13 to 0/18.

    • The p block elements form the last 6 vertical columns of the periodic table.

  • d block elements eg the 3d (Sc-Zn) where the 3d sub-shell is being filled and like wise for the 4d block (Y-Cd), giving 10 elements per block per period from period 4 onwards.

    • The d blocks form horizontal series of metals lying between the s block and p blocks vertical columns of groups (i.e. between groups 1-2 and 3/13 and 0/8/180.

  • The d blocks include the transition metal series of 8 elements, because the 1st and 10th (e.g. Sc and Zn) are not true transition elements.

  • f blocks elements e.g. the 4f and 5f blocks are where the f sub-shells start being filled (14 elements in each block per period from period 6 onwards).

The positions of the s and p blocks of elements in the periodic table and their electron configurations (Groups 1-2, 3/13 to 0/18). 

The position of the 3d, 4d and 5d block elements are coloured in cyan.

For a fuller picture see Periodic Table sub-page 2.

All the elements laid out in the modern full periodic table (no electron configurations)

All the elements laid out in the modern full periodic table (with electron configurations)

The positions of the d block elements in the periodic table, including the transition metal series and their electron configurations (the elements coloured in cyan).

For a fuller picture see Periodic Table sub-page 2.

All the elements laid out in the modern full periodic table (no electron configurations)

All the elements laid out in the modern full periodic table (with electron configurations)

The above images are a bit 'condensed', but clearer diagrams are shown on separate pages, including, in some cases, the f blocks in the table of all 118 known elements.

1. Electron configurations of selected elements, only s, p, 3d & 4d blocks, NOT 4d, 4f, 5d, 5f & 6d blocks

2. All the elements laid out in the modern full periodic table (no electron configurations)

3. Electron configurations of all elements laid out in a compacted modern full periodic table

4. Electron configurations of all elements laid out in expanded modern full periodic table

(These pages need a wide screen resolution to be seen in full)

• The most stable electron configurations

  • When the outer s and p quantum levels and any completely filled inner orbital quantum levels eg 3d or 4f, you get a particularly stable element with minimal chemical reactivity i.e. you get a Noble Gas element [simple electron notation in ()]

    • Z = 2, helium, 1s² = [He] (2)

    • Z = 10, neon, 1s²2s²2p⁶ = [Ne] (2.8)

    • Z = 18, argon, 1s²2s²2p⁶3s²3p⁶ = [Ar] (2.8.8)

    • Z = 36, krypton, [Ar]3d¹⁰4s²4p⁶ = [Kr] (2.8.18.8)

    • Z = 54, xenon, [Kr]4d¹⁰5s²5p⁶ = [Xe]

    • Z = 86, radon, [Xe]5d¹⁰6s²6p⁶ =[Rn]

• What is the electronic basis of Groups of elements? – their 'electronic classification'

  • For groups 1 to 2, and 'old' 3 to 0/'new' notation 13 to 18 (except He), all the elements in the same vertical column have the same outer electron configuration and therefore will be expected to have a very similar chemistry.

    • This gives the electronic basis for Mendeleev's brilliant conception of the periodic table, i.e. laying out all the elements in order of 'atomic weight' and lining them up to give vertical columns of chemically and physically similar elements.

  • For the d blocks of Groups 3 to 12, using the 'new' group number notation, the vertical 'group' connection of similar outer electron configuration is consistent except for V/Nb, Fe/Ru, Co/Rh, Ni/Pd where the 3d/4s and 4d/5s pairs of levels are of very similar energy and small differences in outer electron configuration occur.

    • Never–the–less these pairs of elements show strong similarities as part of the justification for denoting the Transition Metals plus Groups 4 to 0 as Groups 3 to 18.

• What is the electronic basis for the 'series of elements'? – their 'electronic classification'

  • The '1st Transition Metals Series' from Sc to Zn, and other 'horizontal blocks' are sometimes called a 'series' but they are better described as the '3d block' or '3d series of elements' (and, 4d block, 4f block – filling of 4f sub–shell etc.), but a horizontal row of elements, unlike the vertical columns of the eight vertical groups.

    • Why is 'block' better than 'series'?

    • The reference to the electronic structure is very important, the word series is a bit vague!

    • Technically, scandium (Sc, Z = 21) and zinc (Zn, Z = 30), are NOT true transition metals BUT they are true 3d block elements!

    • See Detailed Advanced Level Transition Metal Notes

• What is the overall electronic basis for blocks of elements across the whole of the periodic table?

  • The s–block consists of Groups 1 and 2 where the only outer electrons are in an s sub–energy level orbital (no outer p electrons, 2 per period).

    • Technically, the same applies to hydrogen and helium in period 1.

  • The p–block corresponds to Groups 3 to 0 (old notation) or Groups 13 to 18 (new notation) where the three p sub–energy level orbitals are being filled (6 per period).

  • Starting with period 4, where the first of the d sub–shells is low enough in energy to be filled, there are ten elements 'inserted' between groups 2 and 3, the so–called d blocks of ten elements (the 1st block, the 3d block Sc–Zn is on Period 4).

    • Therefore Sc to Zn form the head elements of Groups 3 to 12 using the 'new' group number notation.

    • Similarly on period 5 there is a 4d block where the 4d sub–shell level is filled.

    • So 10 d block elements per period are now permitted under the quantum number rules.

  • Starting with cerium (Z=58, period 6), see in full table LINK below, there is a further insertion of fourteen elements where the seven f–orbital sub–shell is being filled after the first of the d–block metals and similarly with thorium (Z=90) in period 7 and these are known as the f blocks (14 per period where permitted).

• The full Periodic Table is shown via the link below without the electron configurations, but including the old/new group number notation.

The full modern periodic table (but no electron configurations shown)

(This page needs a wide screen resolution to be seen in full)

Notes:

The Noble Gases have been referred to as Group 0 because they were believed not to form compounds with other elements.

However, since 1961, many compounds of xenon have been prepared including xenon(VIII) oxide, XeO₄, thus attaining the expected maximum possible oxidation state based on the number of electrons in the outer shell, so Group 18 seems most appropriate to use these days for advanced level chemistry courses.

The d block elements are sometimes referred in terms of their vertical columns as Groups 3 to 12, and the subsequent p–block group columns as Groups 13 to 18.

The s p d f blocks are shown via the Periodic Table link above.

TOP OF PAGE and INDEXES

2.5 Electronic configuration of ions and oxidation states

How do you work out the electron arrangement of ions? How do you work out the electron configuration of ions?

In what order to you remove electrons for positive ions? In what order do you add electrons for negative ions?

• The electron configuration of ions:

  • Beware in quoting the configurations for simple ions where, although the order of removal is basically the reverse of the order for filling the energy levels, there is one important exception you should know.

    • For d/transition blocks/series the 4s electrons are 'removed' before the 3d electrons and similarly the 5s electrons are 'removed' before the 4d electrons.

  • Positive ions (cations) are formed by electron loss and the order of removal is the reverse of the order the full electron configuration is written out e.g.

    • sodium atom Na = 1s²2s²2p⁶3s¹ , sodium ion Na⁺ = 1s²2s²2p⁶ = [Ne]

    • calcium atom is Ca = 1s²2s²2p⁶3s²3p⁶4s², calcium ion Ca²⁺ = 1s²2s²2p⁶3s²3p⁶ = [Ar]

    • iron atom Fe =  [Ar]3d⁶4s², iron(II) ion Fe²⁺ = [Ar]3d⁶, and iron(III) ion Fe³⁺ = [Ar]3d⁵

    • germanium atom Ge = [Ar]3d¹⁰4s²4p², germanium(II) ion Ge²⁺ = [Ar]3d¹⁰4s², germanium(IV) ion Ge⁴⁺ = [Ar]3d¹⁰

    • For the s block elements, the maximum positive oxidation state is governed by the number of electrons removed to give a complete a noble gas structure in the covalent or ionic bonding situation.

  • Negative ions (anions) are formed by electron gain and the filling order rule is continued e.g.

    • chlorine Cl = [Ne]3s²3p⁵, chloride ion Cl^– = [Ne]3s²3p⁶ = [Ar]

    • oxygen: O = [He]2s²2p⁴, oxide ion O^2– = [He]2s²2p⁶ = [Ne]

    • phosphorus: P = [Ne]3s²3p³, phosphide ion P^3– = [Ne]3s²3p³ = [Ar]

    • For the p block groups 3/13 to 0/18 the maximum negative oxidation state is governed by the number of electrons needed to complete a noble gas structure in the covalent or ionic bonding situation (restricted to -1 to -4).

• Further comments on oxidation state and electronic structure:

  • For more details see notes on oxidation state and redox reactions.

  • The maximum oxidation state is often, but not always, limited by an inner full noble gas structure with or without a full d/f sub–shell.

  • The maximum oxidation state from Group 1 Alkali Metals (+1) to Group 0/18 Noble Gases (+8) is numerically equal to the number of outer electrons, i.e. those beyond an inner noble gas core or inner noble gas plus a full d/f sub–shell e.g.

    • The maximum oxidation states for Groups 1 to 0 in old notation (now s-block Groups 1-2 and p-block groups 13-18)

    • Group 1, outer electron configuration s¹, eg sodium is +1 in sodium chloride NaCl

    • Group 2, outer electron configuration s², eg magnesium is +2 in magnesium oxide MgO

    • Group 3 (13), outer electron configuration s²p¹, eg aluminium is +3 in aluminium fluoride AlF₃

    • Group 4 (14), outer electron configuration s²p², eg silicon is +4 in silicon dioxide SiO₂

    • Group 5 (15), outer electron configuration s²p³, eg phosphorus is +5 in the phosphate(V) ion PO₄^3–

    • Group 6 (16), outer electron configuration s²p⁴, eg sulfur is +6 in sulfur trioxide SO₃

    • Group 7 (17), outer electron configuration s²p⁵, eg chlorine is +7 in the chlorate(VII) ion ClO₄^–

    • Group 0 (18), outer electron configuration s²p⁶ (except He, just s²), eg xenon is +8 in xenon(VIII) oxide XeO₄

    • The maximum oxidation state pattern for the d blocks is a bit more complicated and the trend goes through a maximum e.g.

    • the maximum observed oxidation states for the 3d block and transition metal series:

    • Sc (+3), Ti (+4), V (+5), Cr (+6), Mn (+7), Fe (+3, maybe +6?), Co (+3), Ni (+3), Cu (+3), Zn (+2)

    • The maximum oxidation state from scandium to manganese (Sc-Mn) equates to the presence of 4 to 7 3d and 4s electrons beyond the inner noble gas core of [Ar], the 'theoretical' ion would have a 3d⁰ structure.

  • Unionised atoms or simple ions with the same electron configuration are referred to as isoelectronic eg

    • ₁₁Na⁺, ₁₂Mg²⁺, ₁₃Al³⁺ and Ne all have the electron configuration 1s²2s²2p⁶ and you can then say the three ions are isoelectronic with neon (10 electrons).

    • ₇N^3-, ₈O^2- and ₉F^- are also all isoelectronic with neon.

    • ₃₀Zn²⁺ and  ₃₂Ge⁴⁺ are both [Ar]3d¹⁰ and so isoelectronic (28 electrons).

    • ₂₅Mn²⁺ and ₂₆Fe³⁺ are both [Ar]3d⁵ and so isoelectronic (23 electrons).

Learning objectives for working out the electron configuration of elements and simple ions

SPECTROSCOPY, the HYDROGEN SPECTRUM and IONISATION ENERGY PATTERNS

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keywords and phrases: revision study notes for AQA Edexcel OCR Salters advanced A level chemistry on how to use the rules on assigning electron arrangements, and how the electron configuration notation is written out, how to use boxes to represent orbitals of electrons, how to explain the relationship between electron configuration and the position of an element in the Periodic Table, using electron configurations to show how the Periodic Table is worked out, explaining an element's position in the Periodic Table and the electronic origin of the element's chemistry, which is due to the arrangement of its outer valency electrons. How to work out the electron configuration of positive and negative ions from the electron configuration of the element and explaining maximum and minimum oxidation sates from the electron configuration of an element. How to work out the electron configurations of the elements Alphabetical order of the elements of the periodic table symbol name atomic number: electron configuration of Ac Actinium 89, electron configuration of Al Aluminium 13, electron configuration of Sb Antimony 51, electron configuration of Ar Argon 18, electron configuration of As Arsenic 33, electron configuration of At Astatine 85, electron configuration of Ba Barium 56, electron configuration of Be Beryllium 4, electron configuration of Bi Bismuth 83, electron configuration of B Boron 5, electron configuration of Br Bromine 35, electron configuration of Cd Cadmium 48, electron configuration of Cs Caesium 55, electron configuration of Ca Calcium 20, electron configuration of C Carbon 6, electron configuration of Ce Cerium 58, electron configuration of Cl Chlorine 17, electron configuration of Cr Chromium 24, electron configuration of Co Cobalt 27, electron configuration of Cu Copper 29, electron configuration of Dy Dysprosium 66, electron configuration of Er Erbium 68, electron configuration of Eu Europium 63, electron configuration of F Fluorine 9, electron configuration of Fr Francium 87, electron configuration of Gd Gadolinium 64, electron configuration of Ga Gallium 31, electron configuration of Ge Germanium 32, electron configuration of Au Gold 79, electron configuration of Hf Hafnium 72, electron configuration of He Helium 2, electron configuration of Ho Holmium 67, electron configuration of H Hydrogen 1, electron configuration of In Indium 49, electron configuration of I Iodine 53, electron configuration of Ir Iridium 77, electron configuration of Fe Iron 26, electron configuration of Kr Krypton 36, electron configuration of La Lanthanum 57, electron configuration of Pb Lead 82, electron configuration of Li Lithium 3, electron configuration of Lu Lutetium 71, electron configuration of Mg Magnesium 12, electron configuration of Mn Manganese 25, electron configuration of Hg Mercury 80, electron configuration of Mo Molybdenum 42, electron configuration of Nd Neodymium 60, electron configuration of Ne Neon 10, electron configuration of Ni Nickel 28, electron configuration of Nb Niobium 41, electron configuration of N Nitrogen 7, electron configuration of Os Osmium 76, electron configuration of O Oxygen 8, electron configuration of Pd Palladium 46, electron configuration of P Phosphorus 15, electron configuration of Pt Platinum 78, electron configuration of Po Polonium 84, electron configuration of K Potassium 19, electron configuration of Pr Praseodymium 59, electron configuration of Pm Promethium 61, electron configuration of Pa Protactinium 91, electron configuration of Ra Radium 88, electron configuration of Rn Radon 86, electron configuration of Re Rhenium 75, electron configuration of Rh Rhodium 45, electron configuration of Rb Rubidium 37, electron configuration of Ru Ruthenium 44, electron configuration of Sm Samarium 62, electron configuration of Sc Scandium 21, electron configuration of Se Selenium 34, electron configuration of Si Silicon 14, electron configuration of Ag Silver 47, electron configuration of Na Sodium 11, electron configuration of Sr Strontium 38, electron configuration of S Sulfur 16, electron configuration of Ta Tantalum 73, electron configuration of Tc Technetium 43, electron configuration of Te Tellurium 52, electron configuration of Tb Terbium 65, electron configuration of Tl Thallium 81, electron configuration of Th Thorium 90, electron configuration of Tm Thulium 69, electron configuration of Sn Tin 50, electron configuration of Ti Titanium 22, electron configuration of W Tungsten 74, electron configuration of U Uranium 92, electron configuration of V Vanadium 23, electron configuration of Xe Xenon 54, electron configuration of Yb Ytterbium 70, electron configuration of Y Yttrium 39, electron configuration of Zn Zinc 30, electron configuration of Zr Zirconium 40, electron configuration of Np Neptunium 93, electron configuration of Pu Plutonium 94, electron configuration of Am Americium 95, electron configuration of Cm Curium 96, electron configuration of Bk Berkelium 97, electron configuration of Cf Californium 98, electron configuration of Es Einsteinium 99, electron configuration of Fm Fermium 100, electron configuration of Md Mendelevium 101, electron configuration of No Nobelium  102, electron configuration of Lr Lawrencium 103, electron configuration of Rf Rutherfordium 104, electron configuration of Db Dubnium 105, electron configuration of Sg Seaborgium 106, electron configuration of Bh Bohrium 107, electron configuration of Hs Hassium 108, electron configuration of Mt Meitnerium 109, electron configuration of Ds Darmstadtium 110, electron configuration of Rg Roentgenium 111, electron configuration of Cn Copernicium 112, electron configuration of Nh Nihonium 113, electron configuration of Fl Flerovium 114, electron configuration of Mc Moscovium 115, electron configuration of Lv Livermorium 116, electron configuration of Ts Tennessine 117, electron configuration of Og Oganesson 118