Lecture 6.2-

e- configs & the Periodic Table

Electron configurations can be shortened by writing the symbol of the previous noble gas in brackets to represent the inside electrons.

Shortened1s2

[He]2s22p6

[Ne]3s23p6

[Ar]3d104s24p6

Elements can be sorted into noble gases, representative elements, transition metals, or inner transition metals based on their electron configurations.

Electron Configurations in Groups

Noble gases (Group 8A) have full outer energy levels. Usually an s2p6 configuration. Helium is full with s2

Electron Configurations in Groups

Electron Configurations in Groups

The Representative Elements (Groups 1,2,13-18 or groups 1A-8A)

Electron Configurations in Groups

The Representative Elements (Groups 1,2,13-18 or groups 1A-8A)

For representative elements s and p sublevels of the highest occupied energy level are not filled.

Electron Configurations in Groups

The Representative Elements (Groups 1,2,13-18 or groups 1A-8A)

For representative elements s and p sublevels of the highest occupied energy level are not filled.

The group number equals the number of electrons in the highest/outermost energy level.

Electron Configurations in Groups

Alkali metals (Group 1A) have one electron in the highest occupied energy level. s1 configuration

Electron Configurations in Groups

Alkaline earth metals (Group 2A) have two electrons in the highest occupied energy level. s2

Electron Configurations in Groups

Halogens(Group 7A) have an s2p5

configuration.

Transition Elements

Transition Elements

There are two types of transition elements—transition metals and inner transition metals. They are classified based on their electron configurations.

Transition Elements

Transition Elements

In transition metals, the highest energy electrons are found in inner d orbitals.

Transition Elements

In transition metals, the highest energy electrons are found in inner d orbitals. In atoms of an inner transition metal, the highest occupied s sublevel and an inner f sublevel contain electrons.

Periods

The period number tells which energy level the outside electrons are in.Ex. 3rd period sodium(Na) is [Ne]3s1

4th period potassium(K) is [Ar]4s1

Blocks of Elements

Using the periodic table, write the electron configuration of N, Ca, Ti, Se, Cl, and He.

Filling orbitals

Positive nucleus

12

3

4

The red circles represent energy levels

Filling orbitals

Positive nucleus

12

3

4

The red circles represent energy levels

H 1e-

1s1

Filling orbitals

Positive nucleus

12

3

4

The red circles represent energy levels

He 2e-

1s2

The first

energy level is full

Filling orbitals

Positive nucleus

12

3

4

The red circles represent energy levels

Helium is a noble gas

1s2 = [He]

All the electrons

that helium has

Filling orbitals

Positive nucleus

12

3

4

The red circles represent energy levels

Li 3e-

1s2 2s1

or [He] 2s1

All the electrons

that helium has

Filling orbitals

Positive nucleus

12

3

4

All the electrons

that helium has

Be 4e-

1s2 2s2

or [He] 2s2

Filling orbitals

Positive nucleus

12

3

4 B 5e-

[He] 2s2 2p1

All the electrons

that helium has

Filling orbitals

Positive nucleus

12

3

4 C 6e-

[He]2s2 2p2

All the electrons

that helium has

Filling orbitals

Positive nucleus

12

3

4 N 7e-

[He]2s2 2p3

All the electrons

that helium has

Filling orbitals

Positive nucleus

12

3

4 O 8e-

[He]2s2 2p4

All the electrons

that helium has

Filling orbitals

Positive nucleus

12

3

4 F 9e-

[He]2s2 2p5

All the electrons

that helium has

Filling orbitals

Positive nucleus

12

3

4 Ne 10e-

[He]2s2 2p6 2nd energy level is full!

All the electrons

that helium has

Filling orbitals

Positive nucleus

12

3

4 Ne 10e-

[He]2s2 2p6 = [Ne]

Neon’s ten electrons

Neon is a noble gas

Filling orbitals

Positive nucleus

12

3

4 Na 11e-

[Ne]3s1

Neon’s ten

electrons

Filling orbitals

Positive nucleus

12

3

4 Mg 12e-

[Ne]3s2

Neon’s ten

electrons

Filling orbitals

Positive nucleus

12

3

4 Al 13e-

[Ne]3s2 3p1

Neon’s ten

electrons

Filling orbitals

Positive nucleus

12

3

4 Si 14e-

[Ne]3s2 3p2

Neon’s ten

electrons

Filling orbitals

Positive nucleus

12

3

4 P 15e-

[Ne]3s2 3p3

Neon’s ten

electrons

Filling orbitals

Positive nucleus

12

3

4 S 16e-

[Ne]3s2 3p4

Neon’s ten

electrons

Filling orbitals

Positive nucleus

12

3

4 Cl 17e-

[Ne]3s2 3p5

Neon’s ten

electrons

Filling orbitals

Positive nucleus

12

3

4 Ar 18e-

[Ne]3s2 3p6

Neon’s ten

electrons

Filling orbitals

Positive nucleus

12

3

4 Ar 18e-

[Ne]3s2 3p6 = [Ar]

Argon is a noble gasArgon’s

18 electrons

Filling orbitals

Positive nucleus

12

3

4 K 19e-

[Ar]4s1

Argon’s 18

electrons

Filling orbitals

Positive nucleus

12

3

4 Ca 20e-

[Ar]4s2

Argon’s 18

electrons

Filling orbitals

Positive nucleus

12

3

4 Sc 21e-

[Ar] 3d1 4s2

Argon’s 18

electrons

Filling orbitals

Positive nucleus

12

3

4 Sc 21e-

[Ar] 3d1 4s2

Argon’s 18

electrons

Transition metals have their highest energy electrons in inner d orbitals

Filling orbitals

Positive nucleus

12

3

4 Ti 22e-

[Ar] 3d2 4s2

Argon’s 18

electrons

Transition metals have their highest energy electrons in inner d orbitals

Filling orbitals

Positive nucleus

12

3

4 V 23e-

[Ar] 3d3 4s2

Argon’s 18

electrons

Filling orbitals

Positive nucleus

12

3

4 Cr 24e-

[Ar] 3d4 4s2

Argon’s 18

electrons

Filling orbitals

Positive nucleus

12

3

4 Mn 25e-

[Ar] 3d5 4s2

Argon’s 18

electrons

Filling orbitals

Positive nucleus

12

3

4 Fe 26e-

[Ar] 3d6 4s2

Argon’s 18

electrons

Filling orbitals

Positive nucleus

12

3

4 Co 27e-

[Ar] 3d7 4s2

Argon’s 18

electrons

Filling orbitals

Positive nucleus

12

3

4 Ni 28e-

[Ar] 3d8 4s2

Argon’s 18

electrons

Filling orbitals

Positive nucleus

12

3

4 Cu 29e-

[Ar] 3d9 4s2

Argon’s 18

electrons

Filling orbitals

Positive nucleus

12

3

4 Zn 30e-

[Ar] 3d10 4s2 The 3rd energy level is full!

Argon’s 18

electrons

Filling orbitals

Positive nucleus

12

3

4 Ga 31e-

[Ar] 3d10 4s2 4p1

Argon’s 18

electrons

Filling orbitals

Positive nucleus

12

3

4 Ge 32e-

[Ar] 3d10 4s2 4p2

Argon’s 18

electrons

Filling orbitals

Positive nucleus

12

3

4 As 33e-

[Ar] 3d10 4s2 4p3

Argon’s 18

electrons

Filling orbitals

Positive nucleus

12

3

4 Se 34e-

[Ar] 3d10 4s2 4p4

Argon’s 18

electrons

Filling orbitals

Positive nucleus

12

3

4 Br 35e-

[Ar] 3d10 4s2 4p5

Argon’s 18

electrons

Filling orbitals

Positive nucleus

12

3

4 Kr 36e-

[Ar] 3d10 4s2 4p6

Argon’s 18

electrons

Filling orbitals

Positive nucleus

12

3

4 Kr 36e-

[Ar]3d104s24p6 = [Kr]

Krypton is a noble gaskrypton’s

36 electrons

5

Filling orbitals

Positive nucleus

12

3

4 Rb 37e-

[Kr] 5s1

Krypton is a noble gaskrypton’s

36 electrons

5

And so on and so forth……