Core notation

Question 1

Steps to Follow When Adding e‐ (negative ions):

Answer 1

• Write out the core notation for the neutral atom –
atom without the extra e‐ added yet
• Add electrons to the next unfilled orbital ‐ add e‐
where the neutral atom left off

Question 2

Steps to follow (rules for cations/positive ions):

Answer 2

1. Write out core notation for the neutral atom
2. Remove e‐ from the orbital with the largest energy
   level first (largest n‐value 1st)
3. Outer e‐ will always be removed before core e‐
   regardless of their energy levels

Question 3

What is the order when further removing electrons in cations?

Answer 3

p before s before d

Question 4

What are the exception group of elements that don’t take part in chemical reactions?

Answer 4

Noble gases

Question 5

Where are VALENCE electrons not found?

Answer 5

‐ the core

‐ filled d or f subshells