Molecular Element/Other things

[Guest ZaP1989]

Hi, I'm taking a grade 11 course and I was wondering if someone could explain a few things for me.

 

What is a molecular element? For example, I have a question that says:

Classify each of the reactants and products as ionic compounds, molecular compounds, or molecular elements.

 

Another question I have is: is there a difference between a covalent bond and a molecular bond? And if there is, what's the difference?

 

Finally: How do you know whether hydrogen is acting as a metal or nonmetal? For example: you have water (H2O). How do you tell if it is ionic or molecular compound? Since hydrogen can go +1 or -1, oxygen goes -2, how do you know if hydrogen gives up 2 electrons to oxygen to form ionic or if it shares the electrons to form molecular/covalent?

 

Thanks for your help!!

Nick

[swansont]

Hi' date=' I'm taking a grade 11 course and I was wondering if someone could explain a few things for me.

 

What is a molecular element? For example, I have a question that says:

Classify each of the reactants and products as ionic compounds, molecular compounds, or molecular elements.

[/quote']

 

I would guess that hydrogen as H₂ would be considered a molecular element, as contrasted with water, H₂O which would be a molecular compound.

[jdurg]

Molecular elements are elements which exist as a compound of more than one atom in their pure form. The elements H, O, N, Cl, Br, I, and F all exist as diatomic molecules in their pure form and not as single atoms like Mercury, Lead, Sodium, etc. Two other elements which actually exist as molecular substances and not as solitary atoms are Phosphorus and Sulfur. However, people generally write them out in equations as P and S and not as P4 and S8 like they should be written as.

 

H2

O2 (O3 if it's ozone)

N2

Cl2

Br2

I2

F2

P4

S8

[Silencer]

I believe that mercury can be diatomic at times as well.

[jdurg]

I believe that mercury can be diatomic at times as well.

 

Yes, but generally only as an ion such as Hg2(2+).

[The Thing]

As for molecular compounds, they are covalent compounds. Ionic compounds are bonded in a giant ionic lattice.

[Ophiolite]

Ionic compounds are bonded in a giant ionic lattice.

Unless there are only eighty seven ions present, then the lattice is quite small.

[Skye]

Finally: How do you know whether hydrogen is acting as a metal or nonmetal? For example: you have water (H2O). How do you tell if it is ionic or molecular compound? Since hydrogen can go +1 or -1, oxygen goes -2, how do you know if hydrogen gives up 2 electrons to oxygen to form ionic or if it shares the electrons to form molecular/covalent?

Whether a bond is ionic or covalent can be determined by the differences in the electronegativity of the elements involved.

 

Scroll down to the electronegativity heading on this link for an explanation:

 

http://neon.chem.uidaho.edu/~honors/electneg.html

[budullewraagh]

make note that this is all very relative

[The Thing]

Unless there are only eighty seven ions present, then the lattice is quite small. [img']http://www.scienceforums.net/forums/images/icons/icon7.gif[/img]

No, the lattice is called Giant Ionic Lattice. Thats the name of it, with the giant in front of it. I don't know why they gave it such a name, but it is called "giant ionic lattice".