Basic Chemistry Questions... (1 Viewer)

[Leap]

I have these worksheets due for Human Biology and Biochemistry, and I haven't done Chem since year 10 so yeah I don't know a lot of the basic stuff.
I was wondering if anyone could help me with a few things that I'm stuck on:

1.Cobalt and Nickel have about the same atomic masses, how is this possible if they have different numbers of protons and electrons?

2. What are the the particles in the Na-23 nucleus

3. Is Carbon more likely to form ionic or covalent compounds?

4.What is the ratio of positive ions to negative ions in
a. Sodium Chloride
b. Potassium Phosphate


so yeah, any help would be great, I'm really bad at Chem

 

[walla]

1. Atomic mass is mainly determined by the number of neutrons and protons - electrons are a relatively insignificant part.
Cobalt - 27 protons and 32 neutrons.
Nickel - 28 protons and 30 neutrons (about 68% of the time) OR 28 protons and 32 neutrons (about 26% of the time).
So usually, cobalt has one less proton and 2 more neutrons than nickel. So it should have a greater mass, but not that much greater because 1 in 4 nickel atoms has 1 more proton and the same number of neutrons, evening it out a bit.
Essentially they are so similar in mass because you don't just take into account protons, but neutrons as well.

2. Na-23 has 11 protons (like all Na atoms) and 12 neutrons (23 -11). Outside the nucleus, but in the atom, are 11 electrons. Of course, we can remove electrons - 1 is commonly removed to make the Na+ ion.

3. Covalent.

4. Sodium chloride, NaCl, is made up of an Na+ ion and a Cl- ion, so it's a 1:1 ratio.
Potassium phosphate, K3(PO4) is made up of 3 K+ ions and 1 PO4 ion so the ratio is 3:1.

Hope this helps.

 

[KeypadSDM]

Originally posted by walla
3. Covalent.

Because the difference between the electronegativity of carbon and that of most other atoms is such that it is less than 3.7(?) difference required to form ionic bonds.

 

[CM_Tutor]

Originally posted by KeypadSDM
Because the difference between the electronegativity of carbon and that of most other atoms is such that it is less than 3.7(?) difference required to form ionic bonds.

2 or 2.1, not 3.7

 

[Collin]

Woah, Keypad was wrong?

I mean.. WOAH?? That can't be right..

 

[CM_Tutor]

Originally posted by JKDDragon
Woah, Keypad was wrong?

I mean.. WOAH?? That can't be right..

Highest Pauling electronegativity on the PT : fluorine, at 3.98
Lowest Pauling electronegativity on the PT: francium, at 0.7
Therefore, maximum possible difference is 3.28.

So, yes, Keypad was wrong - but then he clearly indicated that he wasn't sure of the value by saying "3.7(?)", didn't he?

 

[KeypadSDM]

I was going on what I remembered waaaaaay back in year 11.

Lol, now I remember that Fluorine was 4.0. I was waaay off.

 

[Collin]

It's funny because we didn't even learn the magnitude differences of electronegativity (or whatever you're talking about here), in year 11, or 12.

We had too many dumbarses in our year to slow the academically elite down.

Originally posted by CM_Tutor
Highest Pauling electronegativity on the PT : fluorine, at 3.98
Lowest Pauling electronegativity on the PT: francium, at 0.7
Therefore, maximum possible difference is 3.28.

So, yes, Keypad was wrong - but then he clearly indicated that he wasn't sure of the value by saying "3.7(?)", didn't he?

Next time I'll remember to add a [/sarcasm] notification.

 

[KeypadSDM]

Originally posted by JKDDragon
Next time I'll remember to add a [/sarcasm] notification.

And I'll forget to call you an asshole, just expect it to be implied in my silence.

 

[Collin]

I thought it was always implied?

 

[xiao1985]

Originally posted by KeypadSDM
And I'll forget to call you an asshole, just expect it to be implied in my silence.

Originally posted by JKDDragon
I thought it was always implied?

my god... wut's wif the cyberspacial battle???

y can't human bein live in peace and harmony XD muahahahahhaa

 

[Collin]

Keypad and I aren't fighting. We're buddies, ya know. Just a little battle of wits online, that's all.

 

[Leap]

hey guys, thank you soooo much for your help!

Chem is driving me insane

 

[Collin]

Originally posted by Leap
hey guys, thank you soooo much for your help!

Chem is driving me insane

You must now shout us all to a feast at an expensive French restaurant.