CHEMISTRY COMMUNITY

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Noble gases have a complete octet so they are usually unreactive. Bases have to be either proton acceptors or electron pair donors so noble gases would not be considered bases.

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You use de broglie’s equation to find the wavelength of anything that is not light and has a mass since mass is involved in the equation. Examples of these would be protons, electrons, and ions.

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These prefixes are used for polydentate ligand. For example, if there are two ethylenediamines, it would be bisethylenediamine.

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Lewis acid is an electron pair acceptor and Lewis base is an electron pair donor. Bronstead acids are proton donors and Bronstead bases are proton acceptors.

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Amphiprotic compounds can both donate and receive H+ so they can act as an acid and a base.

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If you score 250/500 points overall, you will automatically get a C-. If you score more than that, there is no curve and your science corresponds with the matching letter grade.

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I think all we need to know is pH<7 is considered to be an acid, pH>7 is considered to be a base, and pH=7 is considered neutral. Also, I think we should know how to find the pH of a solution given the concentration, and vice versa.

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I think acids and bases will be emphasized on the final since we haven't been tested on that yet.

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Water is constant so it doesn't affect acid and base reactions.

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NH₃ is usually a weak base since it accepts a proton to form NH₄⁺.

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The oxidation state of the metal ion is found using the charges of each ligand and the overall charge of the coordination compound. For example, in the coordination compound [Cu(NH 3 ) 4 ] 2+ , the ligand, NH 3 , has a charge of 0 and the compound has an overall charge of 2+. Therefore, Cu has to ha...

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The geometry of a molecule determines its hybridization. A molecule with 3 bonded atoms and one lone pair has tetrahedral geometry since it has 4 regions of electron density. This is why the molecule has a hybridization of sp³ even though the molecule only has three bonding regions.

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Given a chemical equation, you can determine which substance is the acid by counting the hydrogens on each substance before and after the reaction. If the number of hydrogens has decreased, that substance is an acid since acids are hydrogen ion donors.

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A Bronstead-Lowry acid is defined as a substance that donates hydrogen ions, while a Bronstead-Lowry base accepts hydrogen ions. Another way of looking at it is Bronstead-Lowry acids are proton donors, while Bronstead-Lowry bases are proton acceptors. This is the main difference between the two.

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Cisplatin works by attaching itself to DNA in a way that prohibits its function. It bonds to the guanine and adenine bases so the water molecules originally bound to the platinum fall off, and coordinate covalent bonds to the platinum are formed using a lone pair on the nitrogen atom of two guanines...

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Since the sulfite ion has a lone pair, this causes a little more repulsion, causing the bond angles to be slightly less than 109 degrees.

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Using the Valence-Shell Electron-Pair Repulsion Model (VSEPR) to determine the shape of inorganic, organic, and small biological molecules, cations, and anions, using bond dipole moments and shape to determine if a molecule is polar or non-polar, using shape and polar or non-polar properties, identi...

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The electron geometry of ClO2+ is triganol planar since it has three regions of electron density around the central atom. The molecular geometry is bent since there is one lone pair and two bonded atoms around the central atom.

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I don't think we will be asked to calculate the strength of the bonds. We just need to know the trend in strength of bonds, so which bonds are stronger/weaker than the other.

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The VSEPR formula for a compound with tetrahedral shape would be AX₄ since tetrahedral shape molecules have one central atom and 4 atoms bonded to it.

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Van der waals interaction < hydrogen bond < covalent bond < ionic bond

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Atoms with high polarizing power are able to cause large distortions in atoms/ions that are very polarizable. Therefore atoms/ions with small atomic radii have high polarizing power since they have a stronger pull on the polarizable atom/ion's electrons.

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A d subshell can hold a maximum of ten electrons since there are 5 orbitals, and two electrons can fit in each orbital.

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Electronegativity is defined as the tendency of an atom to attract a shared pair of electrons towards itself. Therefore, in a polar bond, the more electronegative atom will attract the electron density toward itself.

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In order to determine whether a molecule is polar or non-polar, you would have to draw out the lewis structure first. Then you would identify the bonds and lone pairs around the central atom. If the molecule has symmetry around the central atom, the dipoles cancel out and the molecule is non-polar. ...

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Free radicals in the body damage living cells and tissues in a process called "oxidative stress." Also, as the body ages, it loses its ability to fight off free radicals and this results in the presence of more free radicals in the body, which leads to more oxidative stress and more damage...

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Oxygen has a lower ionization energy than Nitrogen, which is unexpected according to the periodic trend of ionization energy increasing as you move across a period. This is because an electron being added to an already full orbital in Oxygen will result in electron-electron repulsion, and this will ...

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The Pauli Exclusion principle states that in an atom, or molecule, no two electrons can have the same four quantum numbers since they cannot be at the same place at the same time with the same energy. Also, it states that an orbital can have a maximum of two electrons and electrons in the same orbit...

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A coordinate covalent bond is a type of covalent bond where the two bonding electrons come from the same atom. In a regular covalent bond, each of the atoms that are forming the bond donate an electron to form the bond.

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I don't think you will be asked to draw the Lewis structure of something that general. I think the question would definitely provide the formula for the Lewis structure you are asked to draw.

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You count the electrons individually and not in pairs when calculating formal charge. The formula for calculating formal charge is (number of valence electrons in the neutral atom) - 1/2(number of electrons in covalent bonds) - (number of electrons in lone pairs).

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I don't think we need to know how to calculate specific bond lengths. I think all you need to know is that single bonds have longer bond lengths than double bonds which have longer bond lengths than triple bonds.

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Electrons further away from the nucleus are easier to remove because they experience shielding from the positively charged nucleus by the inner electrons. Therefore, they don't experience as strong of an attraction to the positively charged nucleus and require less energy to remove.

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Ionization energy is always positive because it requires energy to remove electrons (endothermic). The negatively charged electrons are attracted to the positively charged nucleus so it requires extra energy to remove the electrons.

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Quantum numbers are only used to describe the electrons in an element. Therefore, you will not be able to find the specific element given only the quantum numbers.

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The valence electrons of chromium include both its 4s and 3d electrons so it has 6 valence electrons in total.

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The ms quantum number represents the direction of the electron spin. If the electron has an upward spin, ms is equal to positive 1/2. If the electron has a downward spin, ms is equal to negative 1/2.

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All s orbitals are spherical in shape so they have spherical symmetry. Therefore, the wave function only depends on the distance from the nucleus and not the direction. The p, d, and f orbitals do not have symmetry since they are not spherically symmetric.

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Electrons farther from the nucleus have higher energy because they don't feel the attraction of the nucleus as strongly due to shielding of the inner electrons. Therefore, it takes less energy to remove electrons farther from the nucleus, and this means they have higher energy.

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Copper and Chromium are exceptions because it is easier to remove a 4s electron and bring it down to the 3d subshell. This creates more stability due to symmetry since it gives them a half filled or completely filled 3d subshell.

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The photoelectric experiment has to be done in a vacuum because electrons produced close to the threshold have a relatively low energy. Low energy electrons cannot travel very far in the air before they are defected by collisions and this makes then very difficult to detect without a vacuum.

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The speed of light is considered to be constant for our purposes in chemistry, but this is only a postulate since it has not been proved.

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One mole is the number of atoms in exactly 12 g of carbon-12 because the atomic mass scale is defined by the mass of carbon-12. This means that one atomic mass unit is defined to be 1/12 of the mass of a carbon-12 atom. Therefore, the number of atoms in 12.0000...000 grams of carbon-12 is Avogadro's...

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There is a specific order when writing out chemical formulas. For instance, C6H12O6 (glucose) is never written like H12O6C6. Out of convention, carbon is always the first atom to be listed in chemical formulas and hydrogens are next. Other atoms are listed alphabetically thereafter.

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I would recommend only rounding to the correct amount of sig figs when you reach your final answer. I would keep the exact value when doing calculations.

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According to Dalton's atomic theory, atoms of one element cannot be converted into atoms of another element, and atoms can neither be created or destroyed in chemical reactions. The law of conservation of mass also supports this.

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Usually when writing the formula for compounds, you write the cation (atom that is positively charged and this is usually a metal) followed by the anion (atom that is negatively charged and this is usually a nonmetal). In the case of SiH4, Si should be written first since it a metal that has a charg...

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You should balance this equation similar to the way you balance a combustion reaction. Therefore, you should balance the Hydrogens first, then the Nitrogens, then the Oxygens.

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It is definitely good to show all your steps when solving a problem because it will be easier to pinpoint the exact step in which you made an error when you are trying to learn from the problems you got wrong on the test. If you don't show your work, you won't know exactly where you went wrong, whic...

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I think you will need to memorize conversions that are used frequently in chemistry such as 1 L = 1000 mL ,1 kg = 1000g, and Kelvin = Celsius + 273 but I'm not necessarily sure about the conversion from pm to m.

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The molar mass of the molecule will be given if you are to find the molecular formula.

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