Chemistry model help! (1 Viewer)

[jane1820]

I need to make two models: one ionic compound (i chose NaCl) and one covalent compound (i chose H2O)

for the lattice model of NaCl should i make sodium bigger or smaller relative to chloride? Ik that the ion is smaller but the atom is bigger and when i google models (obviously drawn and not physical) they show sodium much bigger relative to chloride

what should i do? Im so puzzled

also for a H2O network, so the hydrogen atoms of one H2O molecule create hydrogen bonds with the oxygen atoms of the neighbouring molecule correct? Just want to make sure its perfect

my assignment is divided into two parts: 2 model + research task and an exam
since the first part is 20% of the grade (exam 10%: add to 30% of yearly grade) i need my model and research task to be perfect, please help

 

[C2H6O]

Na and Cl are in the same period, so because of the fact that atomic radius decreases as you move to the right, Sodium is larger. However, considering that they're ions, sodium will have lost an electron while chlorine has gained one. by losing an electron sodium's atomic radius reduces a lot more because its lost the outermost layer, while chloride's atomic radius only shifts a little. Its kinda like comparing the atomic radii of neon and argon which neon is obviously smaller. So i think sodium should be smaller but if anyone can counter that...

For H2O networks, assuming its liquid then yeah youd have random intermolecular hydrogen bonds between the hydrogens and the exposed side of the oxygens so the entire thing is like a clump of molecules. if it was solid youd arrange it in a hexagonal pattern

 

[wizzkids]

You can look up tables of ionic radii on the Internet, or if you can get hold of a copy of SI Chemical Data by Aylward and Findlay, look up Properties of the Elements, ionic radii in there, in units of picometres.
When sodium and chlorine form an ionic lattice (note- your model must represent a 3-D lattice) sodium gets smaller ( 144 pm -> 115 pm) and chorine gets bigger (99 pm -> 181 pm).
Water is a good choice for the covalent compound, because its properties are so unusual for a covalent compound. You will need to show two types of bonding; the strong covalent bonds, and the relatively much weaker hydrogen bonds.
However modelling the hydrogen bond is going to be tricky.
If you change your mind and you decide to choose a covalent molecular lattice, then graphite or diamond are both interesting choices with lots of interesting properties.

 

[jane1820]

For water i decided to use wooden skewers for the covalent bonds (between oxygen and hydrogen within one molecule) to represent that its hard/strong and chenille stems (i think their name is?) for the hydrogen bonds (between oxygen and hydrogen of neighbouring molecules)

Huge foam balls (i think their name?) for oxygen (for size) and to show its firm but not sure its a good choice

Pompoms for both chloride and hydrogen since they’re gases n light (?)

and playdough for sodium since its soft and malleable

oh and for NaCl ill be using skewers to connect them

anyways any feedback before i start?

 

[jane1820]

are these appropriate images to add as 'scientific diagrams' for my report of explaining covalent/ionic bonds?

 

[Shavi Masee]

View attachment 47093View attachment 47094

are these appropriate images to add as 'scientific diagrams' for my report of explaining covalent/ionic bonds?

if they aren't i've fucked up my chem vid.. T-T
If you're referencing, then just add the link in

 

[jane1820]

if they aren't i've fucked up my chem vid.. T-T
If you're referencing, then just add the link in

im not sure their scientific is all... i might draw my own diagrams on my ipad but add them in the draft report
my draft for the report is due on tuesday so hopefully i would have done it by then

 

[C2H6O]

im not sure their scientific is all... i might draw my own diagrams on my ipad but add them in the draft report
my draft for the report is due on tuesday so hopefully i would have done it by then

For high school chem they're pretty standard, itll probably be alright. Any more scientific and youd have to pull up the spdf orbitals and σ/π-bonds. Seeing as this is just a modelling task focusing on the actual compounds i think that'd be over the top

 

[wizzkids]

are these appropriate images to add as 'scientific diagrams' for my report of explaining covalent/ionic bonds?

The covalent diagram is fine. Covalent bonds are directional and have definite angles between the bonds. Covalent molecules have a molecular weight.
Ionic bonds are very different. Be careful you fully understand what that diagram is saying. That label that says, "ionic molecule" could be quite misleading. There are no molecules in sodium chloride.
In the case of sodium chloride, the bonds are not directional, they are electrostatic forces so they extend equally in all directions. Each sodium ion is surrounded by six chlorine ions, and likewise each chlorine ion is surrounded by six sodium ions. The overall atomic ratio is 1:1 but there is no such thing as a molecular weight. Instead we use an average chemical formula that represents the lowest common multiple of the atomic ratio.