0. (3pts) Write the electron configuration for an Al atom and identify which of these electrons are valence electrons. 1. (3pts) Write the electron configuration for Al3+ and identify which of these electrons are valence electrons. 2. (4pts) How many valence electrons do each of the following atoms have: Sr,Se ? Briefly describe your rationale. 3. (4pts) How many valence electrons do each of the following ions have: K+,Se2 ? Briefly describe your rationale. 4. (3pts) Among the following, determine which have similar chemical properties: Na,Mg,K,K+. Briefly explain 5. (2pts) In your words, describe the meaning of the term orbital. 6. (2pts) Consider a 1s orbital and a 2s orbital. Identify which orbital is further from the nucleus and also which orbital has a lower potential energy