# Few Biologoy Questions

1. Dec 14, 2006

### Kramer

From your knowledge about the distribution of electrons in the levels and from the atomic number (in parentheses), indicate the most likely charge on the ion when this atom forms an ion (Remember the 2, 8, 18 level distribution).

Oxygen (8)

________ ?

From your knowledge about the distribution of electrons in the levels and from the atomic number (in parentheses), indicate the most likely charge on the ion when this atom forms an ion (Remember the 2, 8, 18 level distribution).

Sodium (11)

________ ?

The signed number telling how many electrons an atom will usually receive or lose is the ___________?

Subatomic particles that lack an electric charge are ___________?

A compound which produces H+ ions in solution is a(n) ___________?

Substances which maintain a body's pH within narrow limits are called ___________?

These are some questions on my review i want to get so that i am prepared.Im totally clueless, and iv been looking all through my texbooks and notes to find some the answers.

Hopefully som1 can help

Thanks

2. Dec 14, 2006

### Staff: Mentor

If your teacher wants you to remember facts rather than ideas this kind of thing should have been explicit in your classes.

The first three questions are talking about the "onion layers" that electrons live in as they whizz around. If the outer layer is nearly complete, the valence (number of electrons gained or lost) is negative - oxygen is -2.
Sodium has the exact opposite set up. There is only one electron in the outer shell. So it wants to donate the electron. +1 is the valence.

ion="wrong number of electrons" so the atom becomes charged. If you give up a minus charge you become positive. Sodium makes a postive ion for that reason. If you grab electrons like oxygen does, you have too many so you have a negative charge.

I'll let someonelse finish....

3. Dec 14, 2006

### drpizza

Your ion is going to want to be in a state such that the outer shell is either full, or empty. For oxygen (with 8 electrons), the inner shell is filled with 2 electrons. That leaves 6 electrons in the outer shell. Now, to become an ion, the "choices" are to lose 6 electrons (to have 0 in the outer shell) or gain 2 electrons (for a total of 10, which leaves the outer shell filled with 8). It's much easier to gain 2 than to give up 6, so this is more likely.

It comes down to this (I'll just make up an example that doesn't actually exist.) Let's say the shells had 10, 20, then 50 electron positions in them. Element A has 77 electrons. So, it'll fill the 10 shell, 20 shell, and have 47 left for the 50 shell. Since 47 is closer to 50, it'll prefer to gain 3 electrons (and since electrons have a negative charge, it'll have a -3 charge as an ion.)
Element B has 34 electrons. That gives it 10 for the innermost shell, 20 for the second shell, and 4 left over for the 50 shell. It'll prefer to lose the 4 electrons (rather than gain 46). Thus, since the protons in the nucleus now outnumber the electrons by 4, it'll have a +4 charge.

4. Dec 14, 2006

### cristo

Staff Emeritus
Would it not be more useful to use actual configurations of electrons for real elements, or at least to use shells with the correct number of electrons in (i.e. 2, 8, etc), rather than confuse the student by using electron shells which are completely different to what s/he will have learnt?

5. Dec 15, 2006

### Kramer

Ok i get it, thanks so much

Now these other few questions, still searching through my text book, cant find anything.

The signed number telling how many electrons an atom will usually receive or lose is the __________?

Subatomic particles that lack an electric charge are ______?

A compound which produces H+ ions in solution is a(n) ____________?

Substances which maintain a body's pH within narrow limits are called _______?

6. Dec 15, 2006

### cristo

Staff Emeritus
Name the subatomic particles you know? Which of these has no charge?

7. Dec 15, 2006

### Staff: Mentor

valence is the word I used above.