Questions.. Answers?

[denttiger]

---

Members don't see this ad.

Hey, I just have a couple questions that I'm sure are probably easy but just needed some help with, so if you know the reasoning behind any of these please let me know! Thanks!

1)What is the number of unpaired electrons in this atom? 1s2 2s2 2p6 3s2 3p2
-Easy question.. but I seem to get a different answer than the key..

2)Of the following, the rate and type of cleavage occurring after fertilization would be most affected by the... Answer's

a) "amount and distribution of yolk".
b) "number of chromosomes"
c) "thickness of the cell membrane"
d) "thickness of the zona pellucida"
The answer is a, but can someone tell me why..

3) What is the initial step in the speciation process?

Thanks again! Oh..These questions are from the ADA exam.. I did really really well on it! Bio 19, Gen. Chem. 23, and O. Chem. 28!! 🙂 I know, from looking on this board, that it's not an accurate test compared to the real thing... but is it a good start or should I have made like 30's across the board for the sciences to do well on the real DAT?

 

[slashnroses19]

i can help with question 1. in the p orbital there are 3 empty orbitals. each orbital fills up with a max of 2 electrons. for the p orbital you have to fill in one electron at a time in each orbital. thus you have two unpaired e's for a 3p2. if it was 3p3, you'd have 3 unpaired. if it was 3p4 you'd fill up one of the p orbital completely (2) and 2 orbitals would still have one electron each, thus 2 unpaired electrons.

 

[DailyDrivenTJ]

I just found the following from wikipedia.

Depending mostly on the amount of yolk in the egg, the cleavage can be holoblastic (total or entire cleavage) or meroblastic (partial cleavage)

The entire article.

http://en.wikipedia.org/wiki/Meroblastic

 

[denttiger]

Hey slashnroses19, I got the same answer you did, that there should be two unpaired electrons; however, the answer key says the answer is 1 unpaired electron so that's why I was asking ya'll.. in case I was missing something. I guess maybe the key is just wrong or something. OH.. and thanks DailyDrivenTJ for the answer and article!!

 

[crhoody12]

what is this ADA exam you are talking about (in the original thread) where you got these questions from and is it something online i can print out to take or get somewhere? any extra practice helps...thanks

 

[RozhonDDS]

question 1 is 4 electrons or 2 unparied electrons

 

[denttiger]

hey RozhonDDDs, yeah both slashnroses19 and I both agreed that it should be 2 unpaired electrons but the answer key I have said it should be one.. so that's why I was asking, but thanks for you're input!! And crhoody12, I got the exam from my pre-health advisor so I'm not too sure what to tell you about how to get it.. sorry.