11/29/22 - Electrons and Periodic Trends

Question 1

Does similar electron configuration confer similar chemical behavior?

Answer 1

Yes

Question 2

What are inner electrons?

Answer 2

Those in the noble gas core plus any additional complete d-sublevels

Question 3

What are outer electrons?

Answer 3

Those in the highest occupied energy level (all electrons at the highest n value)

Question 4

Which electrons are valence electrons?

Answer 4

In main-group elements, they are the outer electrons
In transition elements, they are the outer electrons plus the highest d-sublevel electrons

Question 5

Which electrons participate in forming bonds?

Answer 5

Valence

Question 6

The electron configuration for F is
[He]2s^2 2p^5
How many inner electrons are there?

Answer 6

2 from the He

Question 7

The electron configuration for F is
[He]2s^2 2p^5
How many outer electrons are there?

Answer 7

7 because the highest energy level is n = 2, which has 7 electrons

Question 8

The electron configuration for F is
[He]2s^2 2p^5
How many valence electrons are there?

Answer 8

7. F is a main-group element, so the outer electrons are the valence electrons

Question 9

The electron configuration for Cr is
[Ar]4s^1 3d^5
How many inner electrons are there? (Ar is Z = 18)

Answer 9

18 from Ar

Question 10

The electron configuration for Cr is
[Ar]4s^1 3d^5
How many outer electrons are there?

Answer 10

1. The highest energy level is n=4, which has 1 electron.

Question 11

The electron configuration for Cr is
[Ar]4s^1 3d^5
How many valence electrons are there?

Answer 11

6. Cr is a transition element, so its 1 outer electron and 5 3d electrons are valence

Question 12

The electron configuration for Br is
[Ar]4s^2 3d^10 4p^5
How many inner electrons are there? (Ar is Z = 18)

Answer 12

28, there are 18 from Ar and 10 from the complete 3d sublevel

Question 13

The electron configuration for Br is
[Ar]4s^2 3d^10 4p^5
How many outer electrons are there?

Answer 13

7. There are 7 electrons in the n=4 energy level

Question 14

The electron configuration for Br is
[Ar]4s^2 3d^10 4p^5
How many valence electrons are there?

Answer 14

7. As a main group element, the valence electrons of Br are the outer electrons

Question 15

Why is the electron configuration of copper
[Ar]4s^1 3d^10 instead of 4s^2 3d^9?

Answer 15

Because half-filled and fully filled sublevels are more stable.
Likewise Cr is [Ar]4s^1 3d^5

Question 16

Which three properties are influenced by electron configuration and effective nuclear charge?

Answer 16

Atom size, ionization energy, and electron affinity

Question 17

As the principal quantum number (n) increases, does atom size increase or decrease?

Answer 17

Increase

Question 18

As effective nuclear charge increases, does atom size increase or decrease?

Answer 18

Decrease because atoms are pulled closer

Question 19

Atom size is greater:
Top or bottom of the periodic table?
Right or left?

Answer 19

Bottom and left

Question 20

How is atomic radius found?

Answer 20

It is half the distance between the nearest adjacent or bonded atoms