Ionization Energies Mike Jones Pisgah High School Canton NC Revised 11/20/11 05/18/12

Ionization energy The energy needed to remove an electron completely from at atom. Depends upon …. The attraction between the positively charged nucleus and the negatively charged electron. The repulsion between the negatively charged electrons.

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+ 2

+ 2

+ 2

+ 2

+ 2

+ 2

+ 2

+ 2

+ 2 8

+ 2 8

+ 2 8

+ 2 8

+ 2 8

+ 2 8

+ 2 8

+ 2 8

+ 2 8 8

+ 2 8 8

+ 2 8 8 18

+ 2 8 8 18

+ 2 8 8 18 18

+ 2 8 8 18 18

2 + 8 8 18 18 32 2 8 8 18 18

Eight electrons are filling the second energy level. Why does the ionization energy increase along a period?

Why are there “blips” in the ionization energies?

The second energy level must be subdivided into two sublevels each with a different energy. The fifth electron for boron must be in a higher energy level because it takes less additional energy to remove it.

Electrons in the higher sublevel The second energy level must be subdivided into two sublevels each with a different energy. The fifth electron for boron must be in a higher energy level because it takes less additional energy to remove it. Electrons in the lower sublevel

Electrons in the higher sublevel The same is true for the third energy level. Electrons in the lower sublevel

There are many limitations of the Bohr model, including the fact that the calculations work only for hydrogen. But there is one overriding reason why the Bohr model is so important to our study of the atom and the arrangement of electrons. The Bohr model tells us that electrons are located only in certain, discrete energy levels and that they can only change from one energy level to another by gaining or losing energy.

The Bohr model has a few discrete energy levels. 4 An “excited electron” is located in one of these energy levels 3 2 A ground-state electron is located in the lowest energy level. 1

n 2n2 1 2 8 3 18 4 32 5 50 The number of electrons in the nth energy level is given by 2n2. The Bohr model showed only 8 electrons in the third energy level. Where are the other ten electrons?

The Quantum mechanical model has more energy levels available to electrons n is the “principle quantum number, one of 4 numbers that uniquiely describe each electron in an atom 4 n 2n2 1 2 8 3 18 4 32 5 50 3 Except for the first energy level, each energy level in the Bohr model is “subdivided” into two or more “sublevels.” 2 1

In multi-electron atoms the original Bohr energy levels are split into sublevels. 4 n 2n2 1 2 8 3 18 4 32 5 50 3 2 1

In multi-electron atoms the original Bohr energy levels are split into sublevels. 4 n 2n2 1 2 8 3 18 4 32 5 50 3 2 1

Overlap between energy sublevels. In multi-electron atoms the original Bohr energy levels are split into sublevels. 4 Overlap between energy sublevels. n 2n2 1 2 8 3 18 4 32 5 50 3 2 1

The letters s, p, d and f are used to label the sublevels. In multi-electron atoms the original Bohr energy levels are split into sublevels. The letters s, p, d and f are used to label the sublevels. 4f 4d 4 4p n 2n2 1 2 8 3 18 4 32 5 50 3d 4s 3 3p 3s s = sharp p = principle d = diffused f = fundamental 2p 2 2s 1 1s

The letters s, p, d and f are used to label the sublevels. In multi-electron atoms the original Bohr energy levels are split into sublevels. The letters s, p, d and f are used to label the sublevels. 4f 4d 4 32 4p n 2n2 1 2 8 3 18 4 32 5 50 3d 4s 3 3p 18 sublevel number of electrons s 2 p 6 d 10 f 14 3s 2p 2 8 2s 2 1 1s

s p d f 2 6 10 14 Periodic table - Sublevels How many electrons go in each region? 14

Since we can’t see atoms or the electrons we have no idea what they actually look like. Yet we need a way to represent the organization of electrons in an atom. Much like technicians use a schematic diagram to represent the components in an electronic circuit, chemists use the electron energy diagram to represent electrons in an atom.

Much like technicians use a schematic diagram to represent the components in an electronic circuit, chemists use the electron energy diagram to represent electrons in an atom.

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 6s 4f 5d 6p 7s 5f 6d 7p E n e r g y Electron Energy Diagram The electron energy diagram is a schematic diagram representing the arrangement of electrons in an atom. It consists of lines representing the orbitals in the various energy sublevels. n 2n2 1 2 8 3 18 4 32 5 50 s 2 p 6 d 10 f 14

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 6s 4f 5d 6p 7s 5f 6d 7p E n e r g y Electron Energy Diagram Each of the lines represents an “orbital” where up to two electrons can be located. n 2n2 1 2 8 3 18 4 32 5 50 s 2 p 6 d 10 f 14

An orbital is a “region in space” within an atom where up to two electrons can be located. An s-orbital is spherical. Two electrons. The p-orbitals are “dumbell” shaped. Each orbital contains two electrons, for a total of six The Shrodinger wave equation predicts the shape of the orbitals.

The five d-orbitals are shaped like this The five d-orbitals are shaped like this. Each orbital can contain two electrons, for a total of 10 electrons. The transition metals are filling the d-orbitals.

Electron Energy Diagram for Arsenic Each horizontal line represents an orbital, a region which can be occupied by up to two electrons. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p E n e r g y Electrons with opposite spin are represented by up and down arrows. The electron energy diagram represents the arrangement of the electrons in their respective energy levels and sublevels.

Electron Energy Diagram 7p Electron Energy Diagram 6d 5f 7s 6p 5d 4f 6s E n e r g y 5p 4d 5s 4p 3d 4s 3p 3s 2p 2s 1s

Electron Energy Diagram 1s

Electron Energy Diagram The second energy splits into two sublevels called “s” and “p”. An s-sublevel holds two electons. A p-sublevel holds up to six electrons in three orbitals. 2p 2s 1s

Electron Energy Diagram The third energy splits into three sublevels, the “s”, the “p”, and the “d”. The d-sublevel holds up to ten electrons in five orbitals. E n e r g y 3d 3p 3s 2p 2s 1s

Electron Energy Diagram Notice that the 4s sublevel is lower in energy than the 3d sublevel. 4f E n e r g y The fourth energy splits into four sublevels, the “s”, the “p”, the “d”, and the “f ”. The f-sublevel holds up to 14 electrons in seven orbitals. 4d 4p 3d 4s 3p 3s 2p 2s 1s

Electron Energy Diagram 5f 5d 4f E n e r g y 5p Notice the overlap again in the 5s and 4d, and the location of the 4f sublevel. 4d 5s 4p 3d 4s 3p 3s 2p 2s 1s

Electron Energy Diagram 5f 6p 5d 4f 6s E n e r g y 5p The 6s-sublevel is lower in energy than the 4f sublevel. 4d 5s 4p 3d 4s 3p 3s 2p 2s 1s

Electron Energy Diagram 7p Electron Energy Diagram 6d 5f 7s The 7s-sublevel is lower in energy than the 5f sublevel. 6p 5d 4f 6s E n e r g y 5p 4d 5s 4p The energy sublevels are filled in order from lowest energy to highest energy. 3d 4s 3p 3s 2p 2s 1s

Order in which the energy sublevels are filled. 2p 3s 4s 3p 4p 3d 4d 5s 5p 6s 4f 5d 6p 7s 5f 6d 7p E n e r g y Order in which the energy sublevels are filled. Electron Energy Diagram

Periodic table - Sublevels f

Order in which the energy sublevels are filled.

Electron Energy Diagram 7p Electron Energy Diagram 6d 5f 7s 6p 5d 4f 6s E n e r g y 5p 4d The order in which the orbitals are filled can also be predicted from the graph of ionization energy. 5s 4p 3d 4s 3p 3s 2p 2s 1s

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p H 1s

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p He 1s

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p Li 1s 2s

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p Be 1s 2s

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p B 1s 2s 2p

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p C 1s 2s 2p

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p N 1s 2s 2p

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p O 1s 2s 2p

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p F 1s 2s 2p

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p Ne 1s 2s 2p

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p Na 1s 2s 2p 3s

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p Mg 1s 2s 2p 3s

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p Al 1s 2s 2p 3s 3p

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p Si 1s 2s 2p 3s 3p

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p P 1s 2s 2p 3s 3p

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p S 1s 2s 2p 3s 3p

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p Cl 1s 2s 2p 3s 3p

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p Ar 1s 2s 2p 3s 3p

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p K 1s 2s 2p 3s 3p 4s

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p Ca 1s 2s 2p 3s 3p 4s

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p Sc 1s 2s 2p 3s 3p 4s 3d

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p Ti 1s 2s 2p 3s 3p 4s 3d

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p V 1s 2s 2p 3s 3p 4s 3d

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p Cr 1s 2s 2p 3s 3p 4s 3d

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p Mn 1s 2s 2p 3s 3p 4s 3d

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p Fe 1s 2s 2p 3s 3p 4s 3d

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p Co 1s 2s 2p 3s 3p 4s 3d

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p Ni 1s 2s 2p 3s 3p 4s 3d

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p Cu 1s 2s 2p 3s 3p 4s 3d

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p Zn 1s 2s 2p 3s 3p 4s 3d

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p Ga 1s 2s 2p 3s 3p 4s 3d 4p

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p Ge 1s 2s 2p 3s 3p 4s 3d 4p

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p As 1s 2s 2p 3s 3p 4s 3d 4p

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p Se 1s 2s 2p 3s 3p 4s 3d 4p

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p Br 1s 2s 2p 3s 3p 4s 3d 4p

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p Kr 1s 2s 2p 3s 3p 4s 3d 4p

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p Rb 1s 2s 2p 3s 3p 4s 3d 4p 5s

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p Sr 1s 2s 2p 3s 3p 4s 3d 4p 5s

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p Y 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p Tc 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p Cd 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p In 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p Sb 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p Xe 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p

1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p Cs 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p

1s2, 2s2 2p6, 3s2 3p6, 4s2 4p3 Electron Energy Diagram for Arsenic We can represent the arrangement of electrons more simply by using the “electron configuration.” E n e r g y 1s2, 2s2 2p6, 3s2 3p6, 4s2 4p3

1s2, 2s2 2p6, 3s2 3p6, 4s2 4p3 Electron Energy Diagram for Arsenic We can simplify the “electron configuration” even more by using the “inert gas core” to represent the electrons which do not take part in chemical reactions. E n e r g y 1s2, 2s2 2p6, 3s2 3p6, 4s2 4p3

Ar 4s2 4p3 Electron Energy Diagram for Arsenic We can simplify the “electron configuration” even more by using the “inert gas core” to represent the electrons which do not take part in chemical reactions. E n e r g y Ar 4s2 4p3

Electron Energy Diagram for Arsenic Write the electron configuration using the inert gas core for the following elements: 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p E n e r g y 1. Al 4. P 2. V 5. Sn 3. Br 6. Bi Ar 4s2 4p3

1. Al 4. P 2. V 5. Sn 3. Br 6. Bi [Ne] 3s2 3p1 [Ar] 4s2, 3d3 Write the electron configuration using the inert gas core for the following elements: [Ne] 3s2 3p1 [Ar] 4s2, 3d3 [Ar] 4s2, 3d10, 4p5 [Ne] 3s2, 3p3 [Kr] 5s2, 4d10, 5p2 6. [Xe] 6s2, 4f14, 5d10, 6p3 Valence electrons are the outer-most electrons which are involved in bonding. How many valence electrons does each element have?

[Ne] 3s2 3p1 [Ar] 4s2, 3d3 [Ar] 4s2, 3d10, 4p5 [Ne] 3s2, 3p3 The valence electrons have the highest principal quantum number. Look at the Roman numeral at the top of the column for each element. [Ne] 3s2 3p1 [Ar] 4s2, 3d3 [Ar] 4s2, 3d10, 4p5 [Ne] 3s2, 3p3 [Kr] 5s2, 4d10, 5p2 6. [Xe] 6s2, 4f14, 5d10, 6p3 1. Al 3 2. V 5 3. Br 7 4. P 3 5. Sn 4 6. Bi 5

Mike Jones Pisgah High School Canton NC mjones@haywood.k12.nc.us

Spare parts E n e r g y 7p 6d 5f 7s 6p 5d 4f 6s 5p 4d 5s 4p 3d 4s 3p + 4d 5s 4p 3d 4s 3p 3s 2p 2s 1s