CHEMISTRY COMMUNITY

Tae Pasawat 2A

That makes sense. Thank you Andre! Would H3PO4 and HBRO2 not work then then because they don't have an overall negative charge to attract protons? And BrO^2- and PO4^3- are considered bases right? Because their negative charges will attract protons? H3PO4 would not work because the it already has i...

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Just to clarify, resonance only matters when dealing with nonbinary acids like carboxylic acids and oxoacids!

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Hi! The methyl (CH3) group in acetic acid is contributing more electron density to the COOH group. This makes it harder for the OH bond in acetic acid to break. Since formic acid doesn't have that methyl group to stabilize and weaken the acid, it is stronger. Hi Eva! I just wanted to clarify, the m...

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I also wanted to differentiate a simple ionic compound like HCl from a more complex ionic compound with covalent structures within it like HClO2. The simple ionic compounds like HCl and HBr directly shows the strength of the acid by looking at how weak the bond is. More complex acids like HClO2 is m...

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Yes! Two factors to keep in mind is the strength of the bond within the compound and whether it is monoprotic or polyprotic :)

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Hi, thanks so much for your answers. I have another question. Is it a dative bond that connects oxygen to the iron?

Thanks!

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can someone please explain the differences between myoglobin and the heme complex? Thank you!

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I think a ligand is a subset of a lewis base. Lewis base is a general term for species that can donate electrons, but ligands specifically donate electrons to form a large complex (e.g. to a metal ion to form a coordination compound)

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Can someone please explain why a seesaw shape is not possible for complexes with a coordination number as 4? Is it because seesaw has 5 e- density regions (and 4 bonds) and it makes it unstable?

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I see people mentioning that planar shapes would never be ideal for 6 bond, because the electrons want to be as spread out from each other as possible. What number of bonds would be fine being in a planar shape? Common examples of planar shapes are trigonal planar and square planar. Keep in mind th...

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You should look at the whole compound as an ion in which the potassium is the positively charged metal and the hexacyanidochromate(III) is the non metal. The positively charged metal always comes first in the name of an ionic compound: such as sodium chloride.

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Yes! just to clarify, bidentate means that it can bond to the central metal ion twice (take that into consideration of the coordination number too!)

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The hybridization would be sp2 for each carbon. And yes, you are right, a double bond only counts as 1 region of electron density. The shortcut to finding hybridization formulas is to count the number electron density regions (this includes lone pairs). And the indices of the letters in the hybridiz...

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Don't forget that hydrogen will never be placed in the middle. The atom that has the highest ionisation energy will be in the middle!

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Hi everyone! When determining which isomer in this problem is polar or nonpolar, would we just have to look at the dipole moments? Since the 3rd isomer has the two chorines direct opposite from each other, does this mean that the dipole moments cancel out? I was wondering if you guys could explain ...

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Hey Jade! I think where you are going wrong is the number of bonds on carbon. Remember carbon's electron configuration does not have a d-orbital so a carbon atom cannot have more than four bonds. Taking this into consideration, all you have to do is move one of the hydrogens that is bound to the ca...

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Catherine Bubser 2C wrote:Sapling says one of the three structures is cyclic, does that mean it makes a ring?

Yes! but each bond of the ring doesn't always have to be the same! some can be single, double, or triple bonds. Just make sure you satisfy the carbon with 4 bonds and have the correct number of hydroens.

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A bent shape will have 2 lone pairs and two bonding pairs! So it would look like a tetrahedral shape replaced with 2 lone pairs and the 2 bonding pairs will be pushed closer to each other

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Also wanted to clarify that all lewis structures that are possible for a molecule contributes to the resonance structure, its just that the more stable lewis structures dominate in their contribution to the resonance structure. The final resonance structure will be more similar to the most stable le...

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A Resonance hybrid energy is lower than the Lewis resonance structures right? It is more stable but it is delocalized making it lower in energy? I had someone tell me that hybrids are higher in energy... Resonance structures have lower energy because they have a lower formal charge overall, making ...

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this is a bit of a dumb question but what exactly do we mean when we say something is delocalized? i've seen it in a couple of posts and im a bit confused as to what that exactly means Hi the term delocalized is used to refer to an electrons activity! so if it is delocalized, it means that it is no...

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In Dr. Lavelle's lecture, he combines the atomic orbitals from the same shell (n=2) to make hybrid orbitals. Is hybridization the process of making atomic orbitals hybrid? Hi i have a follow up question. Does hybridization only occur for orbitals in the same energy level? can they occur for orbital...

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I think delocalized pi bonds are referring to the electrons within the bond, and not the bond itself because a bond is really just a place where electrons exist. The phrase delocalized pi bonds means that the electrons are delocalized and that the electrons are free to move over more than one nuclei...

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I think your answer is correct as the ion has an expanded octet in which it has an additional 3 electrons in the d orbital, making the number of valence electrons 11.

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Just beware that the term 'ground state' means the ground state of the ion

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Professor Lavelle mentioned that we do not need to memorize bond angles but we need to be able to deduce whether the bond angle would be smaller or larger in comparison to other molecules by looking at the number of e- density regions and how many lone pairs are present!

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Also wanted to add that you can confirm its a radical because it was once C3H6 and it was split in the middle between the CC double bond, making it a radical because the shared e are split.

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No the shape alone cannot tell whether the molecule is polar or non polar. You must also look at the geometry of the molecule. If the geometry is not symmetrical but it has non polar bonds, then the molecule remains non polar. If the molecule is symmetrical and has polar bonds, the dipole moments ar...

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The oxidation numbers can be calculated by looking at the periodic table! The number of e- it loses or gains will be its oxidation number. For example, if oxygen needs to gain 2e- to complete its octet, its oxidation number will be -2. You can also calculate the oxidation number of an element by loo...

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Yes and this is true depsite Ga's electronegativity!

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So the final answer would be 4 possible types of orbitals (3 p orbials and 1 s orbital!)

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It means that the electrons are not forced in a small and local area, they now have the ability to move freely throughout the electron cloud that is formed by the resonance structure.

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Dipole induction can occur between any molecule, whether they are non polar or not. This can come in the form of: 1. Dipole-induced -- dipole-induced 2. Dipole -- dipole-induced Dipole-induced means that it does not have a permanent dipole like a polar bond (with permanent partially positive and neg...

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However, it is important to remember than the 4s is lower in energy than the 3d subshell only for the first 20 elements. So for elements after 20, the electron will be lost from the 4s subshell instead of the 3d subshell. Please also note that Cu is in a special half-filled configuration that you wi...

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Exceptions to the octet rule include electrons exceeding 8 in the valence shell, and also having fewer than 8 electrons. The most common having fewer than 8 is Berylium.

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Because oxygen has 4 electrons in the p subshell, meaning 1 of the p orbitals has 2 electrons with opposite spin. This opposite spin creates repulsion that makes the electron easier to remove.

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In the case that we need to know f orbitals, they can hold 14 electrons!

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What do you mean by parallel? if you mean electrons traveling in the same direction in a single orbital, this is not possible as electrons must always be in an opposite spin as stated by Pauli's exclusion principle. The hunds rule states that electrons will fill different orbitals within a subshell ...

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Hi, Each pair of electrons in an orbital represents two electrons with the same first three quantum numbers and a different fourth quantum number (they must have opposite spins, and thus different ms numbers according to the Pauli exclusion principle). I think you're right that because a P subshell...

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To figure out how many electrons fill each orientation, you have to remember that due to electron repulsion, electrons in the same subshell (s,p,d,f) must occupy different orbitals with parallel spin before adding another electron to the same orbital (Hund's Rule). px, py and pz are the three orien...

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An orbital is a specific location where are pair of e- are likely to be located. An orbital is a SUBSET of a subshell, meaning that there are orbitals situated within a subshell. A subshell is distinguished by the energy level number n and the l number. The l number specifies which of the s, p, d, o...

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This question is confusing because, by intuition, we would expect nitrogen to have a lower IE than oxygen. But this is not true as oxygen has one of its p orbitals with 2 electrons in it. Since the electrons are having opposite spin, there is repulsion, making the electron easier to remove. Although...

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Hi! There are two exceptions 1. Half filled configuration [Sc] When an electron is taken from the 4s orbital to fill the 3d orbitals, this results in 5 electrons in the 3d orbitals. This results in 1 electron per each of the 5 3d orbitals. Hence, the name half-filled since there is 1 electron per or...

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Hi! To expand, to really find the number of electrons there are, you must also look at the l number. The l number shows the number of different orientations of a specific orbital (s,p,d,f) and since each orbital contains a maximum of two electrons and since we can find out which orbitals are present...

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The way i visualize a plan is a flat piece of paper slicing through the diagram, creating cross-sectional areas with the electron cloud.

A nodal plane is where there is no probability of finding an electron, and this is where the different lobes are connected together at a node or central region.

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a) energy of the electron would increase because it is in a higher energy level, meaning that they hold more potential energy to either come back down to the original potential energy. c) But since it is entering a 2p orbital, that means that l=1 from l=0, the l number has changed It is not b becaus...

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Another note that I would like to make its that you do not need to be able to specify the M number, just the range of potential M values :)

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Thomas Vu 3A wrote:
Tae Pasawat 2A wrote:Hi!

I can't seem to find the answers for these questions on sapling. Does anyone have the answers? Thank you so much1

For part a), I got 289.4 m/s and for part b) I got .0229 m/s. So, the lithium ion could be specified more accurately.

Thank you so much!

Tae Pasawat 2A

Hi!

I can't seem to find the answers for these questions on sapling. Does anyone have the answers? Thank you so much1

Tae Pasawat 2A

Hi!
My take on it is that since the electron interacts with the light and changes its path, there is a possibility that its momentum has changed, meaning that the velocity has changed, too. Since momentum = mass x velocity. hope this helps!

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The initial can be seen as where the electron departs, and the final where the electron arrives. So if its an emission, the electron leaves a higher energy level to arrive at a lower energy level, for example.

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Can someone please explain part C? Thank you!

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I think you might be missing the negative signs as it is -hR/n^2 in the equations. Hope this helps :)

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Sometimes the questions doesn't only involve n=1 and n=2, so using nf and ni may be more ideal

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How do we find the kinectic energy of an electron when we are only given velocity? I am aware that the KE equation requires mass as well, but isn't the mass of electron negligible and therefore 0?

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So since they gave you velocity of the ejected electron and the energy required to remove that electron, you can use the equation Ek + E(remove e-)= E(photon) to find the energy of the incident light. You would find Ek by using Ek=1/2(mv^2), plugging in mass of e- and velocity of e-. Then, you'd ad...

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I have another question, since we mainly look at the energy level an electron falls down to to dictate what series it belongs to, Professor Lavelle emphasized that this is because the energy level it falls down to gives a good idea of the energy difference. If, for example, an electron falls down to...

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Professor Lavelle said that waves are a classical model of light, meaning that they are viewed on a larger scale and can be seen as continuous. The second model is the photon model where the energy of light is discrete as the photons are individual particles that are not continuous. Since the wave m...

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Energy level means the shells an atom has. And these energy levels are quantized, meaning that an electron cannot exist in between these energy levels (shells), they can only exist discretely on one or another. And for an electron to go from a lower energy level to the higher energy level, it takes ...

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Intensity can be seen as the brightness of the light. This brightness is constituted by the number (quantity) of photons. The energy of light is seen as the color of the light itself, and not the brightness. A different color means that each individual photon has a different energy level. So a diffe...

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I do not understand how to write a net ionic equation.

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6- In Thailand

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UPDATE! There is a typo in the question. The correct reactant for the third equation should be Fe3Br8!

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I can't seem to balance this equation (Fundamental Question E. 35). Is there an algebraic method anyone can hopefully demonstrate? Thank you so much!

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Where can I access the answers to the textbook questions on the Macmillan vital source textbook viewer?

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