CHEM AND BIO HELP AND TIPS HERE

[Baladya]

A new isotope of a divalent metal is discovered. Some students are asked to predict its
properties.
Which student’s predictions are correct?


number of electrons  -  bonding in the oxide
in outer shell
                                     
A      2                                covalent
B      2                                  ionic
C      6                                covalent
D      6                                  ionic

Why is it B and not D?

I think its because they said "metal"

[Shazizzzle]

A new isotope of a divalent metal is discovered. Some students are asked to predict its
properties.
Which student’s predictions are correct?


number of electrons  -  bonding in the oxide
in outer shell
                                     
A      2                                covalent
B      2                                  ionic
C      6                                covalent
D      6                                  ionic

Why is it B and not D?

Firstly because it is a METAL so its valency must be 2, and cannot be 6, because it would be a non-metal then.
Secondly because, it's a METAL OXIDE, which is ionic, i.e metal and non metal.

[Ghost Of Highbury]

anyone tell me what the test of water related to cobalt chloride..
when is it pink and when is it beomes blue ??

When water is added to cobalt chloride, cobalt chloride turns from blue to pink

[nid404]

A new isotope of a divalent metal is discovered. Some students are asked to predict its
properties.
Which student’s predictions are correct?


number of electrons  -  bonding in the oxide
in outer shell
                                     
A      2                                covalent
B      2                                  ionic
C      6                                covalent
D      6                                  ionic

Why is it B and not D?

First you need to understand the term valency and valence electrons.
Valency is the no of electrons required to lose/gain/share in order to achieve a stable electronic configuration.
Valence electrons are the no of electrons in the outermost shell of the atom.

Divalent= 2 valence electrons
So B

[SNA]

hello...can sumone help me?
im sure this is a very easy question and that everyone can answer except for me!
how does the proton number influence the periodic table?
please help!thanksss!

[Ivo]

hello...can sumone help me?
im sure this is a very easy question and that everyone can answer except for me!
how does the proton number influence the periodic table?
please help!thanksss!

Very easy, proton number determines the element.  If you look at 1 particular period on the periodic table, then you'll see when proton number increases by 1, the element is the next group in the same period.  Got it?

[SNA]

Very easy, proton number determines the element.  If you look at 1 particular period on the periodic table, then you'll see when proton number increases by 1, the element is the next group in the same period.  Got it?

got it!thanks!
and do u happen to know any example for intimate mixing?

[Fastal]

if you lose 15 marks in bio paper 3, is it still possible to get an A*

[Ghost Of Highbury]

if you lose 15 marks in bio paper 3, is it still possible to get an A*

What about paper 1 and 6?

[Fastal]

What about paper 1 and 6?

i get 32/40in paper 6 and 38/40 in paper 1 and 65-70/80 in paper 3

[holtadit]

i get 32/40in paper 6 and 38/40 in paper 1 and 65-70/80 in paper 3

It all depends on your Paper 3 performance.

I wish you the best - study hard and concentrate. Pray for me too. 

[sarasa]

I HAVE A DOUBT THAT I CANNOT JUST GET!!
the question gave the height of precipitates with different volumes of one of the soluble salts dat were reacted 2 give da ppt nd we have to find the formula of the other soluble salt.
SO HOW DO WE FIND IT???

[sarasa]

Here is one example ...
It came as a graph in paper3 may/june 2009 Q5

[sarasa]

Here is another question, can u explain how we can we get da formula for both questions, plz?

[Helium]

Have no idea how to do it ,
but doin research to find out cause i also need to know.