4. ATOMIC AND ELECTRONIC STRUCTURE (PART 2)

Question 1

1. What is Quantum Mechanics?

Answer 1

• it is a branch of science that deals with matter on the sub-microscopic level

Sub-Microscopic= atomic

Question 2

2. What does Quantum Mechanics give us?

Answer 2

• it gives us an accurate description of how atoms and molecules behave
• it can also give an accurate description of how electrons in an atom behave and how they are are arranged around the nucleus

Question 3

3. What are electrons responsible for?

Answer 3

• the chemical properties of an element

Question 4

4. What is the Quantum Mechanical Picture?

Answer 4

• it is a statistical theory

Question 5

5. Which space do electrons occupy?

Answer 5

• the space around the nucleus
• this space resembles orbits (like how the moon orbits around the Earth)

Question 6

6. What Theory must be applied to determine the true picture?

Answer 6

• the Quantum Theory

Question 7

7. In which forms can electrons be perceived as?

Answer 7

• waves
• particles
• this is determined by the observer and the tests run by the observer

Question 8

8. Which equation is this?
   What does it solve for?

Answer 8

• the Schrodinger Equation
• also known as the wave equation
• it solves for the motion of the electron

Question 9

9. What is the explicit form of the Schrodinger Equation?

Answer 9

Question 10

10. What kind of energy does this part of the equation represent?

Answer 10

• Kinetic Energy

Question 11

11. What kind of energy does this part of the equation represent?

Answer 11

• Potential Energy

Question 12

12. Label the following parts of the equation?

12.1: Pink Part
12.2: Blue Part
12.3: Yellow Part

Answer 12

12.1: The Hamiltonian

12.2: Energies of the system

12.3: Wave Functions

Question 13

13. What is the Hamiltonian Operator?

Answer 13

• it is the sum of the kinetic and potential energies of the system
• the system is the atom and specifically the electrons distribution in the atom

Question 14

14. What are the Energies of the system (E)?

Answer 14

• when looking at the electron distribution in the atom, the E are the energies of the individual orbitals
• Orbitals are the homes of the electrons

Question 15

15. What are the Wave Functions

Answer 15

• they are functions that contain all the possible information of the system
• the square of the wave function gives the probability of finding the electron in a specific region of space around the nucleus
• this corresponds with the shape of the specific orbital

Question 16

16. What are Orbitals?

Answer 16

• they are the regions around the nucleus where electrons exist and can be found
• they are the mathematical solutions
• they are specific electron cloud fomations

Question 17

17. What are the electrons attracted to?

Answer 17

• the positive nucleus
• this is according to Coulomb’s Law
• the electron stays near to the nucleus because of this charge

Question 18

18. What kind of shape is an “s” orbital?

Answer 18

• it is circularly shaped

Question 19

19. What kind of shape is a “p” orbital?

Answer 19

• it is dumbbell/infinity sign shaped

Question 20

20. What happens to the probability of finding an electron the further away from the nucleus you move?

Answer 20

• the probabilities drop
• you are less likely to find an electron the further away you move from the central nucleus
• the distribution of electron density thins out the further away from the nucleus we move

Question 21

21. What is needed to move the electron further from the nucleus?

Answer 21

• energy
• this is because the electron is attracted to the positive nucleus

Question 22

22. What 3 attributes are specific to each orbital?

Answer 22

1. Shape
2. Size
3. Three- Dimensional Orientations

NB: there is a specific quantum number for each of these

Question 23

23. What is a quantum number?

Answer 23

• it is a numerical index that provides a specific description for a given orbital

Question 24

24. What shape does a “d” orbital have?

Answer 24

• it is clover shaped
• this is also known as a double dumbbell shape

Question 25

25. What shape does an "f" orbital have?

Answer 25

- it has no definite shape due to its complexity

Question 26

26. What is "L" in orbital terms?

Answer 26

- it is the Orbital Angular Momentum (Azimuthal) Quantum Number - it defines the shape of the Orbital

Question 27

27. What is the numerical value of the following letters representing sub-shells? 27.1: s 27.2: p 27.3: d 27.4: f

Answer 27

27.1: 0 27.2: 1 27.3: 2 27.4: 3

Question 28

28. What is the Principle Quantum number (n)?

Answer 28

-is the number in front of the letter - as the principle quantum number increases, so does the overall size of the orbital

Question 29

29. 2s and 3s Orbitals are not solid throughout. There is empty space in certain places. What is this empty space called?

Answer 29

- nodes

Question 30

30. What is a node?

Answer 30

- it is a region where the probability of finding an electron is exactly zero - this only happens with "s" type orbitals

Question 31

31. How do you work out how many nodes an orbital has?

Answer 31

- you use the formula: n-1 - FOR EXAMPLE: a 2s orbital has 1 node BECAUSE: 2-1=1

Question 32

32. What happens to the size of the Orbital as the value of "n" increases?

Answer 32

- the "p" and the "s" orbitals will grow in size

Question 33

33. What is the 3D- Orientation of the Orbital established by?

Answer 33

- it is established by the Magnetic Quantum Number (mL)

Question 34

34. What are the three ways that the Orbitals can be oriented?

Answer 34

- along the Z Axis (Pz) - along the X Axis (Px) - along the Y Axis (Py)

Question 35

35. Read through this summary. Do you understand everything?

Answer 35

- yes