These are all review questions for my summer assignment.

Do not know:
!) Explain what an ionic lattice is and include a diagram.

2)Draw a diagram to show how Na and CL2 combine to form NaCl

Unsure:
!)Select two compounds and explain when Roman numerals are used in the name of an ionic compound and when they are not used.
Roman Numerals are used only when the metal has more than one charge. For example, Cu can have either a +2 or +1 charge, while Zn has one charge, +2. In Cu(II)SO4, the roman numerals are used so scientists can see that when Cu and SO4 combine, Cu becomes a +2 not a +1. But for ZnS04, the roman numerals are not necessary since Zn only has one charge.

An ionic lattice is a repeating arrangement in three dimensions for ionic compounds like NaCl. We can't draw diagrams on this forum but here is a link.

https://www.google.com/search?q=ionic+lattice&tbm=isch&tbo=u&source=univ&sa=X&ei=t2iYVc-rOsyMNu2dgig&ved=0CB4QsAQ&biw=1014&bih=600

Here is another link that talks more about how the arrangements but the pictures, in my opinion, are not as good.
https://www.wou.edu/las/physci/ch412/lattice.html

On the Roman numerals thing you have the right idea but a little off base. The Roman numerals are used in the NAME of the substance, not in the formula. Your explanation is ok because you don't differentiate between formula or name but the idea is this.
If you want to talk about copper sulfate, you write it copper(II) sulfate so you will know the valence of Cu is +2 and not +1. You don't need that for the formula of CuSO4 because you know SO4 is -2 so Cu MUST be +2. ZnSO4 is named. The same is true for iron(II) and iron(III) compounds such as FeCl2 and FeCl3. It isn't necessary, as you point out for ZnSO4 since Zn doesn't have variable valences (oxidation states). In summary, CuSO4 is named copper(II) sulfate and ZnSO4 is names zinc sulfate. Personally, I don't object if someone names ZnSO4 as zinc(II) sulfate but I think purists object.

For the diagram of NaCl (I didn't look at the second link if that would help me with this question, yet) would me drawing what Na and Cl look like in the arrangement of their atoms before and after they combine be good enough?

No, I don't think that would show the 3-D arrangement. I think I want to draw Na ion and Cl and them repeating in 3D as in the first link I gave you.

To explain what an ionic lattice is and include a diagram, you would need to understand the concept of ions and their arrangement in a crystal structure.

An ionic lattice is a three-dimensional arrangement of positive and negative ions held together by ionic bonds. In an ionic compound, which consists of a metal and a non-metal, the metal donates electrons to the non-metal, resulting in the formation of ions. The positive ions (cations) are usually metals, and the negative ions (anions) are usually non-metals.

To visualize an ionic lattice, you can draw a diagram. Let's take the example of sodium chloride (NaCl). Sodium (Na) donates one electron to chlorine (Cl), resulting in the formation of Na+ and Cl- ions. In the diagram, you can represent the sodium ion as Na+ and the chloride ion as Cl-.

The Na+ and Cl- ions arrange themselves in a repeating pattern or lattice structure. Each sodium ion is surrounded by six chloride ions, and each chloride ion is surrounded by six sodium ions. The cations and anions are arranged in a way that the charges balance out, resulting in a stable crystal lattice.

Na+ Cl-
Cl- Na+

This diagram represents a small section of the ionic lattice, but in reality, the lattice extends in all three dimensions.

Now, moving on to the question of how sodium (Na) and chlorine (Cl2) combine to form sodium chloride (NaCl), you would need to understand the concept of chemical bonding.

When sodium reacts with chlorine, each sodium atom donates one electron to a chlorine atom. This electron transfer leads to the formation of sodium ions (Na+) and chloride ions (Cl-). The sodium ion, which lost one electron, has a net positive charge, while the chloride ion, which gained one electron, has a net negative charge. These oppositely charged ions are then attracted to each other, forming an ionic bond.

To draw a diagram showing how Na and Cl2 combine to form NaCl, you can represent the sodium atom as Na and the chlorine molecules as Cl2. You can then show the transfer of electrons between the Na and Cl2 to form NaCl.

Na + Cl2 -> NaCl

In this balanced chemical equation, one sodium atom reacts with one chlorine molecule to produce one sodium chloride molecule.

I hope this explanation helps you understand what an ionic lattice is and how Na and Cl2 combine to form NaCl. Remember, diagrams are a helpful tool to visualize these concepts.