Topic 5-Electron Configuration

Question 1

What does ms stand for? What does it refer to?

Answer 1

ms stands for the electron spin quantum number. It refers to the direction of spin.

Question 2

How many quantum numbers do we need to define an atomic orbital? How many quantum numbers do we need to identify an electron?

Answer 2

3.

4.

Question 3

What are 2 features from radial probability distribution curves.

Answer 3

1. Radial probability is almost zero near the nucleus (even tho electron density is highest)
2. In the 1s orbital, electron is most probably found @ about 5.3E-11 m from the nucleus which is consistent with Bohr’s first radius (5.29E-11 m)

Question 4

What is the penetration or electrons?

Answer 4

The unusual findings of electrons near the nucleus. (small bumps, NOT the big ones)

Question 5

Why is the 2s subshell more stable than the 2p?

Answer 5

This is because in the 2s orbital, the penetration of the electrons is much closer to the nucleus than the 2p orbital.

Question 6

What are the two effects of penetration?

Answer 6

1. It increases the nuclear attraction of the 2s electron than the 2p electron
2. It shields the 2p electron from the nuclear attraction.

Question 7

Which atom has the higher ionization energy, H or He+? Which one is more stable? Why?

Answer 7

He+ (for both)
Although they have 1 electron each, He+ has 2 p+ in its nucleus; therefore, there is a stronger attraction those protons have on the electron.

Question 8

Which atom has a higher ionization energy, He+ or He? Which one is more stable? Why?

Answer 8

He+ (for both)
This is because He has two electrons which would cause shielding. Each electron repels each other making it easier to remove.

Question 9

What is the effect of the nuclear charge of an atom?

Answer 9

1. Higher nuclear charge increases attraction on the electron–the orbital is more stable.
2. Electrons that penetrate would have a higher ionization energy (because they are closer to the nucleus)
3. Electrons that are shielding have lower ionization energy due to the repulsion b/w electrons.

Question 10

What is the Pauli Exclusion Principle?

Answer 10

It states that ‘No two electrons in an atom have the same set of four quantum numbers.

Question 11

What is Hund’s rule?

Answer 11

When degenerate orbitals of identical energy are available, electrons initially occupy these orbitals singly with the same spins before they are paired.

Question 12

How is the electron configuration of a cation formed?

Answer 12

Cation configuration are formed by losing electrons until a noble gas electron configuration is achieved.