Exam questions....

A couple questions have come in for tomorrow's exam.....

Just wondering if any like light waves, Hz questions from chapter seven are
going to be on the test..?!

That info is fair game for the exam...BUT think about how much time we spent on it. We spent maybe a day or two on that info, but we spent WEEKS talking about electron configurations, periodic trends, Lewis structures, VSEPR... The exam will reflect this, if there is a question about light, it will probably be a small question...

could you please explain how to determine which charges are best for elements?? i'm having a hard time understanding just how to find the ones your looking for, could you explain in an email??

Relatively stable ions are formed by relatively stable electron configurations. Electrons are relatively stable when: 1)all the shells are full; 2)all the subshells are full; 3)the subshells are half full. Let's look at a couple examples.
1) Sodium forms a relatively stable ion with a +1 charge because when a sodium atom loses an electron it has the same electron configuration as neon, which has full shells.
1s²2s²2p⁶3s¹ --> ²2s²2p⁶
2) Zinc forms a relatively stable ion with a +2 charge because when a zinc atom loses two electrons all of the occupied subshells are full.
[Ar]4s²3d¹⁰ --> [Ar]3d¹⁰
3) Manganese forms a relatively stable ion with a +2 charge because when a manganese atom loses 2 electrons all of the occupied subshells are either full or half full.
[Ar]4s²3d⁵ --> [Ar]3d⁵
If you're looking for stable ions, write out the electron configuration for the neutral atom and look at how many electrons you have to add or remove to get to full or half full subshells.

I'll be off-line until tomorrow morning, if you have other questions either drop me an email or post a comment to the blog and I'll answer them as soon as I get in. If you notice a question posted to the blog and would like to help out your classmates, feel free to post a follow-up comment to answer the question. See you all tomorrow.