Chemistry HELP ?

Question

The total number of oxygen atoms indicated by the formula Fe - sub 2 ( CO sub 3 )3 is ?


How many atoms of hydrogen are in 3 molecules of Ch sub 4 Cl sub 1 ?

What forms a cation ?

What is the formula for the compunds that would be formed from the following ions?

Na + and Cl ---
Al 3 ( the 2 is like top right of l , ithink its charge ? ) and Br --
K+ and S 2- ---
Mg2 and Cl --

Answer 1

1.9 [ Fe2(CO3)3 contains 2 Fe, 3 C and 3*3 O]
2.12 probably, but there is no such compound as CH4Cl. It must be
CH3Cl, if so then the answer is 9.
3. Loss of one or electron from the valence shell of a metallic atom.
4. NaCl
AlBr3
K2S
MgCl2

Hope this helps.

Answer 2

Fe2(CO3)3 has 3 lots of the -CO3 mixed in for every 2 Fe ions. Therefore it refers to 9 oxygen atoms.

CH4Cl doesn't make much sense.
CH4 is methane and has 4 hydrogens for every carbon atom.
HCl is hydrochloric acid and has 1 hydrogen for every 1 Chlorine.

A cation is formed when a metal loses its outer shell electron. This means the atom as a whole now becomes positive.
For example - take Na (sodium) and rip off the outer electron (not too hard to do as it is a little unstable just by itself and looking to lose the electron) and you have the sodium ion (Na+) which is a cation. Any of the metals (the elements on the left side of the periodic table) will do this.

Na+ and Cl- form NaCl
Cl does not like to gain THREE electrons. It prefers to form a Cl- anion (opposite of cation when you GAIN the electron)
AlBr - I don't remember the oxidation states of these. Check to see if you have the same - let me look it up
K2S usually
MgCl2 Magnesium usually forms a Mg++ cation (losing 2 electrons and having 2 plusses if you like). Cl likes to gain ONE electron and so if you have two Cl's for every Mg you do okay.

Okay aluminium (Al) usually likes to lose 3 outer electrons and Br prefers to gain 1

So you would get AlBr3

Answer 3

1-9
2-12
3-i don't know
4-NaCl
5-Al2Br3
6-K2S
7-MgCl2