Electron configuration

Question 1

What is the maximum no. electrons an orbital can hold?

Answer 1

2

Question 2

What is the maximum no. electrons each subshell can hold?

Answer 2

1s = 2
2s = 2
2p = 6
3s = 2
3p = 6
4s = 2
3d = 10
4p = 6
4d = 10
4f = 14

Question 3

What is the shape of an s orbital?

Answer 3

Spherical

Question 4

What is the shape of a p orbital?

Answer 4

Dumbbell

Question 5

How many orbitals group together for s, p, d and f?

Answer 5

s = 1 orbital 
p = 3 orbitals 
d = 5 orbitals 
f = 7 orbitals

Question 6

Why is 4s lower than 3d in the quantum model?

Answer 6

Because it has less energy

Question 7

What is the electron configuration of K (19 electrons)?

Answer 7

1s(2)2s(2)2p(6)3s(2)3p(6)4s(1)

Question 8

What is shorthand electron configuration?

Answer 8

Simplifying things further by using the previous noble gas symbol

e.g. Ca = [Ar]4s(2)

Question 9

What is the definition of an orbital?

Answer 9

A region within an atom that can hold up to 2 electrons with opposite spins

Question 10

Where are s, p, d and f blocks in the Periodic table?

Answer 10

s block = groups 1 and 2
p block = right hand side
d block = transition metals (middle)
f block = elements at the bottom (rarely used)

Question 11

How does the electron configuration of ions work?

Answer 11

• For positive ions, remove electrons from the OUTER shell first (electrons will be removed from 4s before 3d)
• For negative ions, add electrons to the outer shell to fill it up