Chemistry
zarkam21:

What is the electron pair structure (electron geometry), shape (molecular shape), bond angle, bond polarity, and or molecular polarity for the following ions, compounds, or molecules? SiCL4 SF4

5 months ago
Vocaloid:

you'd start w/ the lewis structure and then make the electron pair structure + and molecular shape based on the number of bonds and lone pairs

5 months ago
Vocaloid:

|dw:1540103900836:dw|

5 months ago
Vocaloid:

rip well whenever you get back, for SiCl4 I got 4 bonds + 0 lone pairs, so what would that be

5 months ago
zarkam21:

|dw:1540161547971:dw|

5 months ago
zarkam21:

Whenever you get back ! =)

5 months ago
Vocaloid:

Si = 4 valence electrons Cl = 7 valence electrons so 4 + 4(7) = 32 electrons = 16 pairs so you need to fill up all lone pairs on chlorines. there shouldn't be any leftover electrons on silicon

5 months ago
Vocaloid:

|dw:1540164298779:dw|

5 months ago
Vocaloid:

anyway, so that's 4 bonds and 0 lone pairs on the central atom (only consider lone pairs on the central atom for this) so the electron geometry and shape are both tetrahedral, bond angle is 109.5 degrees bond polarity, well, idk if they're looking for a quantitative or qualitative response, you would have to check your textbook for the electronegativity values of S and Cl and subtract them, then classify the bond between S and Cl based on that the overall molecule is nonpolar since the bond polarities cancel out (4 equal bonds)

5 months ago
Vocaloid:

still there?

5 months ago
zarkam21:

Yes i am

5 months ago
zarkam21:

so fro bond polarity i would just say that they cancel out

5 months ago
Vocaloid:

$$\color{#0cbb34}{\text{Originally Posted by}}$$ @Vocaloid bond polarity: you would have to check your textbook for the electronegativity values of Si and Cl and subtract them, then classify the bond between Si and Cl based on that $$\color{#0cbb34}{\text{End of Quote}}$$

5 months ago
zarkam21:

electornegstivity for Si is 1.9

5 months ago
zarkam21:

cl is -3

5 months ago
Vocaloid:

should be +3

5 months ago
Vocaloid:

then you'd subtract 3 - 1.9 and check your book to see how your book classifies it (polar, nonpolar, covalent, etc.)

5 months ago
zarkam21:

nonpolar

5 months ago
zarkam21:

=1.1

5 months ago
Vocaloid:

|dw:1540167638922:dw| your book might be slightly different but an electronegativity difference of 1.1 should put it into the polar not nonpolar category

5 months ago
Vocaloid:

so the bond polarity = polar, while the overall molecule polarity = nonpolar

5 months ago
Vocaloid:

you'll repeat this process for SF4

5 months ago
zarkam21:

|dw:1540171221123:dw|

5 months ago
Vocaloid:

sulfur (6 valence) fluorine (7 valence) so 6 + 4(7) = 34, or 17 pairs of electrons, so there should only be 1 electron pair on the central atom

5 months ago
zarkam21:

is it good otherwise

5 months ago
Vocaloid:

yes

5 months ago
Vocaloid:

then check the chart for the number of lone pairs and bonds to see what the electron and molecular geometries are https://s-media-cache-ak0.pinimg.com/736x/62/14/b5/6214b5e947f25877e06d9ac7654ee088.jpg

5 months ago
zarkam21:

so four bonds 0 lone pairs. geometry and shape are tethrahedral bond angle is 109.5

5 months ago
Vocaloid:

there's a lone pair on the central atom, so 1 lone pair not 0.

5 months ago
zarkam21:

the geometry and shape are tetrahedral?

5 months ago
Vocaloid:

check the chart again

5 months ago
Vocaloid:

4 bonds 1 lone pair.

5 months ago
zarkam21:

trigonal bipyramid and seesaw

5 months ago
Vocaloid:

good bond angles for this one are complex but it's about ~90 deg, 180 deg, 120 degrees

5 months ago
Vocaloid:

then find the bond polarity based on the EN's of S and F

5 months ago
zarkam21:

2.58 and 3.98

5 months ago
Vocaloid:

alright so what's the EN difference?

5 months ago
zarkam21:

which one do you subtract from? The most electronegative?

5 months ago
Vocaloid:

higher value - lower value yes

5 months ago
zarkam21:

3.98-2.58=1.4

5 months ago
Vocaloid:

good so what kind of bond would this be? polar, nonpolar, etc.?

5 months ago
zarkam21:

polar covalent

5 months ago
Vocaloid:

good any ideas about the whole molecule's polarity? as a hint consider the lone electron pair on the central atom

5 months ago
zarkam21:

IOnic?

5 months ago
Vocaloid:

is the whole molecular polar or nonpolar?

5 months ago
zarkam21:

polar so nonpolar=?

5 months ago
Vocaloid:

the whole molecule is polar, (due to the lone e' pair) so that's it

5 months ago