Experiment 11- Electron configurations and Orbital diagrams PDF

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Experiment 11: Electron configurations and Orbital diagrams Required reading: Ebbing, 11th Edition Chapter 8. -Electron spin and the Pauli exclusion principle -Building up principle -Electron configurations -Orbital diagrams, Hund’s rule Learning Goals: • To analyze and explain if an orbital diagram follows the Pauli exclusion principle and Hund’s rule • To understand how to write electron configurations and orbital diagrams. • To relate orbital diagrams with magnetic properties. Background information and theory: According to the Bohr model of the atom, an atom consists on a very dense nucleus that contains positive particles called protons, and neutral particles called neutrons. Around this dense nucleus negatively charged particles called electrons are found in orbits or shells of specific energy. The mass of these electrons is about 1/1800 the mass of a proton. The shells where the electrons are found are labeled with a number n (principal quantum number). These shells contain subshells and the subshells consist in orbitals where we can find the electrons. The electron configuration of an atom or ion is a short description of the location of the electrons in different shells and subshells. The ground-state electron configuration is the configuration associated with the lowest energy level of the atom. To write the ground state electron configuration of atom electrons are added to the different shells and subshells using the Aufbau principle or building up principle (see diagram below) 7s

7p

7d

7f

6s

6p

6d

6f

5s

5p

5d

5f

4s

4p

4d

4f

3s

3p

3d

2s

2p

1s

START HERE

When using this diagram, electrons will be first added to the lowest energy level (1s) where up to two electrons can be placed (s subshell). If more electrons need to be

accommodated, they will occupy the different subshells according to the diagram. Superscripts next to the subshell indicate how many electrons have been placed in that subshell. The maximum occupancy for a p subshell is 6 electrons, for a d subshell is 10 and for an f subshell is 14 electrons. For example, the electron configuration of Lithium is written as: 1s2 2s1 Other configurations different than the ground state configuration are called excited state configurations. These are higher in energy. The electron configuration gives you limited information as it tells about the shell and subshell occupancy. An orbital diagram shows you the distribution of the electrons in the different orbitals. In an orbital diagram, an orbital is represented by either a circle or a line. Electrons are represented as arrows. For example, the orbital diagram for an atom of Lithium will be:

1s

2s

In some diagrams, the orbitals are placed in order of increasing energy. Orbital diagrams are useful to predict magnetic properties of elements. A paramagnetic substance has at least one electron alone in an orbital. A diamagnetic substance has all electrons paired up in the orbital diagram. According to this, then Lithium is a paramagnetic substance. When adding electrons in an orbital diagram the electrons must be added with different spins (one pointing up the other down, Pauli exclusion principle). When electrons are added to degenerated orbitals, orbital with the same energy as the 3 p orbitals in a p subshell, these electrons will occupy different orbitals before they pair up (Hund’s rule). The electron configuration of carbon is 1s2 2s2 2p2.and its orbital diagram will look like:

2p

2s

1s From this diagram we can see that carbon is paramagnetic.

In this lab you will observe some orbital diagrams and you will decide if they are correct according to the Pauli exclusion principle and if they follow Hund’s rule.. You will write ground state electron configurations for some of the substances presented following the Aufbau principle. At the end, you will predict magnetic properties for some of these substances. To learn more about writing electron configurations for atoms and ions watch this video: https://lonestar.techsmithrelay.com/diM2 You can also watch: https://www.youtube.com/watch?v=vp9mfW7dqE0 Procedure: Watch the video provided in the link below. In this video, orbital diagrams are sketched for eight different substances. Some of this diagrams are not correctly drawn and some others won’t represent the ground state for the substance. Answer the questions in the data pages as you watch the video. Link to lab video: https://lonestar.techsmithrelay.com/bGx3

Name: _Judy Pham______ Electron configurations and Orbital Diagrams Data There are eight substances in the videos. For each, answer the following questions as you watch the video. Substance 1: 1) For the first substance, draw an orbital diagram like the one in the video. Don’t forget to label each subshell as 1s, 2s, 2p, etc. Use circles, squares or lines to represent orbitals and arrows to represent electrons. 1s 2s 2p

2) Is this diagram possible according to the Pauli exclusion principle? Explain. •

Yes, no electrons have the same quantum number as demonstrated in the model.

3) Observe the order in which the electrons were added to the diagram. Does this example follow the Aufbau principle? Explain. •

Yes, the subshells were filled in order of “counting up” where the 1s shell must be filled before 2s and so on.

4) Observe the process of adding electrons to the orbitals in the orbital diagram, does it follow Hund’s rule? Explain •

I do not think the process for substance 1 in the video follows Hund’s rule because it did not wait till all the shells were once full before doubling up.

5) Write the ground state electron configuration for substance 1. •

1s22s22p2

6) What element is substance 1 according to the ground-state electron configuration you wrote? •

Carbon

Substance 2: 7) For the second substance, draw an orbital diagram like the one in the video. Don’t forget to label each subshell as 1s, 2s, 2p, etc. Use circles, squares or lines to represent orbitals and arrows to represent electrons. 1s

2s

2p

2p

2p

3s 8) Is this diagram possible according to the Pauli exclusion principle? Explain. •

Yes, no two electrons have the same quantum number.

9) Observe the order in which the electrons were added to the diagram. Does this example follow the Aufbau principle? Explain. •

Yes, the electrons were added to the diagram in ascending order.

10) Observe the process of adding electrons to the orbitals in the orbital diagram, does it follow Hund’s rule? Explain •

No, the electrons were not added once before being doubled.

11) Write the ground state electron configuration for substance 2. •

1s22s22p63s2

12) What element is substance 2 according to the ground-state electron configuration you wrote? •

Magnesium

Substance 3: 13) For the third substance, draw an orbital diagram like the one in the video. Don’t forget to label each subshell as 1s, 2s, 2p, etc. Use circles, squares or lines to represent orbitals and arrows to represent electrons.

1s

2s

2p

2p

2p

3s 14) Is this diagram possible according to the Pauli exclusion principle? Explain. •

Yes, no two electrons have the same quantum number.

15) Observe the order in which the electrons were added to the diagram. Does this example follow the Aufbau principle? Explain.

•

Yes, the shells were filled in ascending order.

16) Observe the process of adding electrons to the orbitals in the orbital diagram, does it follow Hund’s rule? Explain •

Yes, the shells were filled once before being doubled.

17) Do you expect this substance to be paramagnetic or diamagnetic? Explain •

I expect this substance to be paramagnetic because all of the shells are doubly filled/full.

Substance 4: 18) For the fourth substance, draw an orbital diagram like the one in the video. Don’t forget to label each subshell as 1s, 2s, 2p, etc. Use circles, squares or lines to represent orbitals and arrows to represent electrons.

2s

2p

2p

2p

1s

3s

3p

3p

3p

3d

3d

19) Is this diagram possible according to the Pauli exclusion principle? Explain.

•

Yes, no two electrons share the same quantum number.

20) Observe the order in which the electrons were added to the diagram. Does this example follow the Aufbau principle? Explain.

•

Yes, the shells were filled in an ascending order.

21) Write the electron configuration for substance 4 according to the orbital diagram in the video.

•

1s22s22p63s23p63d2

22) Substance 4 has two positive charges on it. What is the identity of substance 4 according to the electron configuration you wrote? (Hint: cations are formed by removing electrons from the shell with the largest principal quantum number, n) •

Vanadium 2+

23) According to the orbital diagram, do you expect this substance to be paramagnetic or diamagnetic? Explain •

I expect the substance to be diamagnetic because of its positive charges.

Substance 5: 24) For the fifth substance, draw an orbital diagram like the one in the video. Don’t forget to label each subshell as 1s, 2s, 2p, etc. Use circles, squares or lines to represent orbitals and arrows to represent electrons.

1s

2s

2p

2p

2p

25) Is this diagram possible according to the Pauli exclusion principle? Explain. •

Yes, no two electrons are sharing the same quantum number.

26) Observe the order in which the electrons were added to the diagram. Does this example follow the Aufbau principle? Explain. •

Yes, the shells were filled in ascending order so the Aufbau principle was followed.

27) Observe the process of adding electrons to the orbitals in the orbital diagram, does it follow Hund’s rule? Explain •

Yes, Hund’s rule was followed because the electrons were added in the shell once before doubling.

28) Write the ground state electron configuration for substance 5. •

1s22s22p4

29) What element was substance 5 according to the ground state electron configuration? •

Oxygen

30) Do you expect this substance to be paramagnetic or diamagnetic? Explain •

I expect the substance to be diamagnetic because all of the shells were not filled up.

Substance 6: 31) For the sixth substance, draw an orbital diagram like the one in the video. Don’t forget to label each subshell as 1s, 2s, 2p, etc. Use circles, squares or lines to represent orbitals and arrows to represent electrons.

1s

2s

2p

2p

2p

3s

3p

3d

3d

3p

3p

3d

4s

3d 3d

32) Is this diagram possible according to the Pauli exclusion principle? Explain. •

Yes, no two electrons have the same quantum number.

33) Observe the order in which the electrons were added to the diagram. Does this example follow the Aufbau principle? Explain. •

Yes, the shells were filled in numeric order.

34) Observe the process of adding electrons to the orbitals in the orbital diagram, does it follow Hund’s rule? Explain •

Yes, Hund’s rule was followed because the shells were filled once before being doubled.

35) Write the ground state electron configuration for substance 6 •

1s22s22p63s23p64s23d7

36) What element is substance 6 according to the ground state electron configuration? •

Cobalt

37) Do you expect this substance to be paramagnetic or diamagnetic? Explain •

I expect this substance to be diamagnetic because of its last three shells; they are not full.

Substance 7: 38) For the seventh substance, draw an orbital diagram like the one in the video. Don’t forget to label each subshell as 1s, 2s, 2p, etc. Use circles, squares or lines to represent orbitals and arrows to represent electrons.

1s

2s

2p

2p

2p

3p

3p

3d

3d

3s

3p 3d

39) Is this diagram possible according to the Pauli exclusion principle? Explain. •

Yes, no two same electrons share a quantum number/shell.

40) Observe the order in which the electrons were added to the diagram. Does this example follow the Aufbau principle? Explain. •

Yes, the electrons did follow the order.

Substance 8: 41) For the eighth substance, draw an orbital diagram like the one in the video. Don’t forget to label each subshell as 1s, 2s, 2p, etc. Use circles, squares or lines to represent orbitals and arrows to represent electrons.

1s

2s

2p

2p

2p

3s

42) Is this diagram possible according to the Pauli exclusion principle? Explain. •

No, two electrons are sharing the same quantum number.

43) Observe the order in which the electrons were added to the diagram. Does this example follow the Aufbau principle? Explain. •

Yes, the electrons were added according to the ascending order.

44) Observe the process of adding electrons to the orbitals in the orbital diagram, does it follow Hund’s rule? Explain •

Yes, the electrons did not double until there was one already in the shell.

Name: _Judy Pham______ Electron configurations and Orbital Diagrams Postlab questions: Your instructor may ask you to answer these in your lab notebook, or to answer directly on this page and turn it in, or to include these answers in a formal lab report. Follow your instructor’s directions. 1. Write the electron configuration of the following atoms or ions: Na ____1s22s22p63s1_______________________________________ N3- ____1s22s22p6_________________________________________ Mn ______[Ar] 3d54s2__________________________________________ Zn2+ ______[Ar] 3d10__________________________________________

2. What is the noble gas electron configuration of the following atoms and ions? Fe3+ [Ar] 4s23d6 Si

[Ne] 3s23p2

F

[He] 2s22p5

Se2- [Ar] 4s23d104p4

3. Draw the orbital diagram for Se. Write the electron configuration and indicate if the element is paramagnetic or diamagnetic

1s

2s

4s

2p

3d

2p

3d

2p

3d

3s

3d

3p

3d

3p

4p

4p

Electron configuration: 1s22s22p63s23p64s23d104p4 The element is paramagnetic because all of the shells are filled completely....