CHEMISTRY COMMUNITY

Michelle Shin 4B

How is an anion stabilized?

Michelle Shin 4B

Can neutralization only occur between a strong acid and metal hydroxide or can it occur between weak acids and bases as well?

Michelle Shin 4B

What makes thymine a base?

Michelle Shin 4B

For part a, F- would donate an electron pair (lewis base) to the PF5, which accepts the electron pair (lewis acid). Therefore, the product would be PF6-.

Michelle Shin 4B

A ligand is a polydentate if it donates at least 2 electron pairs.

Michelle Shin 4B

Strong acids and bases completely ionize while weak acids and bases only partially ionize. Strong acids produce many H+ ions and strong bases produce many OH- ions.

Michelle Shin 4B

A conjugate acid is the species that is formed after the base accepts a proton, and a conjugate base is formed after an acid donates a proton. Bronsted acids are defined as H+ donors while Lewis acids are defined as electron pair acceptors.

Michelle Shin 4B

How do you determine the roman numerals when naming a coordination compound, and how do you know you need to include them in the name?

Michelle Shin 4B

A chelate is a complex containing a ligand that forms a ring of atoms that includes the central metal atom. For example, CuC2N2 is a chelate where a ring of atoms is formed including the central metal atom, copper.

Michelle Shin 4B

Acids donate H+ ions(proton) and bases accept H+. Bases also produce OH- while acids produce H+. If you compare the hydrogens before and after a reaction, you can tell if the substance is an acid (decrease H+ =acid) or a base (increase=base).

Michelle Shin 4B

Ligands directly attached to the central ion make up the first coordination sphere, and the second coordination sphere consists of atoms/molecules attached to those in the first coordination sphere. Everything inside the brackets will be inside the coordination sphere.

Michelle Shin 4B

Do all transition metals form coordination compounds or just the ones mentioned in lecture?

Michelle Shin 4B

Ligands are electron pair donors that have at least one lone pair.

Michelle Shin 4B

A ligand is also an electron pair donor, so it must have at least one or more lone pairs.

Michelle Shin 4B

Yes, and there are also two pi bonds and one sigma bond in a triple bond.

Michelle Shin 4B

In Xenon Tetrafluoride (XeF4), it breaks the octet rule to achieve a formal charge of zero in addition to it being higher than n=3.

Michelle Shin 4B

Linear: 180
Trigonal Planar: 120
Tetrahedral: 109.5
Trigonal Pyramidal: trigonal bond angles are 120 while the axial bond angles are 90 and 180
Octahedral: 90 and 180

If there are lone pairs, they repel so the bond angle is smaller.
Ex: NH3 has bond angles of 107 instead of 109.5

Michelle Shin 4B

Sigma bonds are also generally stronger than pi bonds and sigma can exist independently.

Michelle Shin 4B

I believe we only need to know that it is less than a specific bond angle because it can differ for molecules such as H2O (104.5) and NH3 (107).

Michelle Shin 4B

The repulsion caused by the lone pairs results in a smaller bond angle. For example, NH3 is trigonal pyramidal because is has one lone pair and has a bond angle of 107 instead of 109.

Michelle Shin 4B

Stronger bonds have higher boiling points because it takes more energy to boil. Ionic and Hydrogen bonds have higher boiling points while covalent bonds usually have lower boiling points.

Michelle Shin 4B

A single bond has one sigma bond. In a double bond, there is one sigma and one pi bond. In a triple bond, there is one sigma bond and 2 pi bonds.

Michelle Shin 4B

What is the difference between the AT and GC base pairs in the hydrogen bonding example used in lecture?

Michelle Shin 4B

Increasing covalent character is when the electrons get further from the nucleus and it becomes easier to share electrons with other atoms. As the polarizability of anion increase and the polarizing power of a cation increases, the covalent character also increases.

Michelle Shin 4B

Because I2 is a bigger molecule, it has stronger London dispersion forces.

Michelle Shin 4B

After counting the number of valence electrons for each atom, use single bonds and put lone pairs on the atoms starting from the outside. Consider formal charge when drawing lewis structures to determine whether or not to use double bonds and make sure the total number of electrons matches that of t...

Michelle Shin 4B

In the lecture, we went over how the best version of CNS- is when the formal charge of -1 is on the S. Why is the formal charge of -1 on sulfur and not on nitrogen?

Michelle Shin 4B

Having the formal charge for each individual atom equal zero is usually best as well as minimizing the total formal charge.

Michelle Shin 4B

Schrodinger's wave function equation uses the concept that an electron with wave-like properties and indeterminacy in momentum and position can be described by a wave function. This equation can also be solved for 1 electron atoms.

Michelle Shin 4B

The dissociation energy also increases as the difference between the electronegativity of atoms increases.

Michelle Shin 4B

The best structure would be with the double bond between oxygen and nitrogen and a single bond between nitrogen and fluorine since this would result in all the formal charges being zero (the best structure).

Michelle Shin 4B

An electron will be removed from the 4s orbital because the 4s orbital has a lower energy than 3d. 4s has higher energy when when the 4s state is occupied AND electrons enter the 3d state.

Michelle Shin 4B

What are the shared electrons (S) for the formula FC= V -(L + (S/2)) and how do you count them?

Michelle Shin 4B

The elements P, S, and Cl can accommodate more than 8 valence electrons since atoms in period 3 or higher have d-orbitals that can accommodate more electrons.

Michelle Shin 4B

Comparing the formal charges of atoms in Lewis structures helps you find which is the more stable structure, but I'm not sure if this is the only method to see which is the best structure.

Michelle Shin 4B

Because the waves broaden and the extent of change decreases when the frequency decreases, c is the correct answer.

Michelle Shin 4B

The magnetic quantum number labels different orbitals of a subshell (orientation) that an electron occupies.

Michelle Shin 4B

Why is the electron configuration of scandium [Ar] 3d^1 4s^2 and not [Ar] 4s^2 3d^1 ?

Michelle Shin 4B

You start using the d orbital after the 4s state since the 4s state is slightly lower energy than 3d.

Michelle Shin 4B

Electric cars do not have wavelike properties because the properties are negligible, and yes, you should convert it to m/s.

Michelle Shin 4B

The wavelength changes, but the frequency remains constant in order to conserve energy.

Michelle Shin 4B

Electromagnetic waves are the result of a disturbance in the electromagnetic field.

Michelle Shin 4B

The equation is En=-hR/n^2. This applies only to atoms with one electron (hydrogen) because if there were more, then they would repel each other.

Michelle Shin 4B

The wavelike properties are the diffraction patterns: constructive (waves in phase) and destructive interference (waves out of phase).

Michelle Shin 4B

Yes I believe this is used to calculate the energy levels in hydrogen and will only work for atoms with a single electron.

Michelle Shin 4B

Yes you're right about using various ratios to get to the end answer. For example, when you are trying to convert 100 meters per sec to meters per minute, you would begin with the given 100m/s and multiply by the ratio 60sec/1 min since you are trying to solve for meters per minute. The seconds woul...

Michelle Shin 4B

Also make sure to only round for sig figs at the end of your calculations to ensure that you get the most accurate answer possible.

Michelle Shin 4B

I think for the molar masses given in the periodic table you should round to two places after the decimal, which I believe is generally the rule of thumb.

Michelle Shin 4B

To balance Fe2P (s) + S(s) -> P4S10 (s) + FeS(s), how do you know which element to start balancing first?

Michelle Shin 4B

For sig figs make sure to use the smallest value of sig figs in the given (ex. 4.00 is 3 sig figs) and also use at the end of calculations.

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