covalency

Covalent

Summary:  “Are you a carbon sample?  Because I want to date you.

AN: A little Nalu college AU drabble.  This was going to be a lame restaurant AU, and somehow turned into a lame chemistry pun restaurant AU… I can’t stand chemistry (Except I did write all the chem facts off the top of my head, so I’m rather proud of myself) but if someone was passionate about it, I’d love to listen.  PASSION IS ADORABLE

Found on fanfiction.net here.


“Your pink boy is here, Lu.”

Lucy spun around immediately at Mirajane’s words, pausing in her tedious cleaning of the liquor shelves to see her white-haired friend grinning mischievously.  When she stood on her tiptoes to see over Mira’s brother, Elfman, at the bar, sure enough, in walked the love of her life.

Well, not that he knew he was the love of her life, but surely they’d get to that point eventually.  

Natsu Dragneel, the most attractive guy in her university’s sophomore class and in the universe in general (in her opinion, at least), was wandering towards a small booth close to the counter.  Mira said that he was a regular, but tended to come on days that Lucy had off for her book club.  Finally… here he was.  Adding some nice decoration to her day.

Not, of course, that she loved him for his looks.  No, it was ever since that one day together in the Japanese class that they shared.

Keep reading

I googled science pick-up lines and I was not disappointed
  • You’re so hot, you denature my proteins. 
  • Do you have 11 protons? ‘Cause you’re Sodium fine!  
  • You make my anoxic sediments want to increase their redox potential. 
  • I’m more attracted to you than F is attracted to an electron. 
  • We fit together like the sticky ends of recombinant DNA. 
  • You’re hotter than a bunsen burner set to full power. 
  • If I were a neurotransmitter, I would be dopamine so I could activate your reward pathway. 
  • According to the second law of thermodynamics, you’re supposed to share your hotness with me. 
  • How about me and you go back to my place and form a covalent bond?
  • I wish I were Adenine because then I could get paired with U.
  • If you were C6, and I were H12, all we would need is the air we breathe to be sweeter than sugar.
  • I want to stick to u like glue-cose.
  • You must be the one for me, since my selectively permeable membrane let you through. 
4

Physical Properties of Gallium: Ga

Gallium does not crystallize in any of the simple crystal structures. The stable phase under normal conditions isorthorhombic with 8 atoms in the conventional unit cell. Within a unit cell, each atom has only one nearest neighbor (at a distance of 244 pm). The remaining six unit cell neighbors are spaced 27, 30 and 39 pm farther away, and they are grouped in pairs with the same distance. Many stable and metastable phases are found as function of temperature and pressure.

The bonding between the two nearest neighbors is covalent, hence Ga2 dimers are seen as the fundamental building blocks of the crystal. This explains the drop of the melting point compared to its neighbor elements aluminium and indium.

The physical properties of gallium are highly anisotropic, i.e. have different values along the three major crystallographical axes a, b, and c (see table); for this reason, there is a significant difference between the linear (α) and volume thermal expansion coefficients. The properties of gallium are also strongly temperature-dependent, especially near the melting point. For example, the thermal expansion coefficient increases by several hundred percent upon melting. (x)

More science and gifs on: rudescience
Giffed from: this video

The Breakbeat Poets: New American Poetry in the Age of Hip-Hop edited by Kevin Coval, Quraysh Ali Lansana, and Nate Marshall

Hip-Hop is the largest youth culture in the history of the planet rock. This is the first poetry anthology by and for the Hip-Hop generation.

It has produced generations of artists who have revolutionized their genre(s) by applying the aesthetic innovations of the culture. The BreakBeat Poets features 78 poets, born somewhere between 1961-1999, All-City and Coast-to-Coast, who are creating the next and now movement(s) in American letters.  [book link]

covalently-bonded-larry replied to your postAsfhjl why why is he gettin papped with her

Ok but what’s the next phase? Is DC going to get of the car during the exchange? Will there be a verbal altercation? Will DC grab B’s Mexico necklace and fling it across the parking lot? Who will Louis protect: DC or little Freddie…or better yet his cigarette? Stay tuned for the next episode of Babygate brought to you by Adidas and Starbucks.

all jokes aside i’ve honestly been expecting the day we get either a live snapchat or pap pics of louis and briana fighting in a parking lot and i hate that that wouldn’t even be completely unbelievable at this point a;lsdkjlksdj

3

Lennard-Jones Potential

The Lennard-Jones model consists of two ‘parts’; a steep repulsive term, and smoother attractive term, representing the London dispersion forces. Apart from being an important model in itself, the Lennard-Jones potential frequently forms one of ‘building blocks’ of many force fields. It is worth mentioning that the 12-6 Lennard-Jones model is not the most faithful representation of the potential energy surface, but rather its use is widespread due to its computational expediency.The Lennard-Jones Potential is given by the following equation:

V=4ϵ[(σ/r)^12−(σ/r)^6]
where

  • V is the intermolecular potential between the two atoms or molecules.
  • ϵ is the well depth and a measure of how strongly the two particles attract each other.
  • σ is the distance at which the intermolecular potential between the two particles is zero (See Figure 1.2). σ gives a measurement of how close two nonbonding particles can get and is thus referred to as the van der Waals radius. It is equal to one-half of the internuclear distance between nonbonding particles. 
  • r is the distance of separation between both particles (measured from the center of one particle to the center of the other particle).
  • Minimum value of Φ12® at r=rmin

The stability of an arrangement of atoms is a function of the Lennard-Jones separation distance. As the separation distance decreases below equilibrium, the potential energy becomes increasingly positive (indicating a repulsive force). Such a large potential energy is energetically unfavorable, as it indicates an overlapping of atomic orbitals.  However, at long separation distances, the potential energy is negative and approaches zero as the separation distance increases to infinity (indicating an attractive force). This indicates that at long-range distances, the pair of atoms or molecules experiences a small stabilizing force. Lastly, as the separation between the two particles reaches a distance slightly greater than σ, the potential energy reaches a minimum value (indicating zero force).  At this point, the pair of particles is most stable and will remain in that orientation until an external force is exerted upon it. 

This gives rise to Bond Dissociation energy 

1.2.2: Bonding

Ionic bonding: the electrostatic attraction between oppositely charged ions.

Ionic boning is usually found in compounds made of a metal and a non-metal. The metal loses electrons and forms a positive ion, the non-metal gains electrons and forms a negative ion. Dot and cross diagrams can be drawn for ionic compounds, showing the simplest whole number ratio - e.g. NaCl would show one Na⁺ ion and one Cl⁻ ion, and MgCl₂ would show one Mg²⁺ ion and two Cl⁻ ions. 

The arrangement of ions in an ionic solid is described as a giant ionic lattice, as the ions all fit together in a regular pattern:

This structure gives ionic substances many of its properties:

  • High melting and boiling points: because the electrostatic attraction between the +ve and -ve charges  is very strong. Also, the larger the charges of the ions are, the stronger those attractions are the higher the melting point/boiling point will be. 
  • Conduct electricity only when molten or dissolved: because the +ve/-ve ions are fixed in place in the lattice when solid, there are no mobile charge carriers, and thus nothing to conduct electricity. However when molten or in solution, the ions can move and carry charge, thus it conducts electricity. 
  • Soluble in water: because the δ- charge on the oxygen and the δ+ on the hydrogen of the water molecule are attracted to the + and - charges of the ions, and this attraction is strong enough to pull the ionic lattice apart. 
  • Brittle: when a force is applied to an ionic substance, the lattice is deformed and ions with like charges will become aligned. Like charges repel, and this repulsion is enough to split the crystalline structure

Covalent bond: a bond formed by a shared pair of electrons

A group of atoms bonded covalently is called a molecule, and these can also be shown through dot and cross diagrams. Because the electrons are shared, not taken, they look different to ionic dot and cross diagrams. 

Rules for forming covalent bonds:

  1. Unpaired electrons pair up
  2. The maximum number of electrons that can pair up is equal to the number of electrons in the outer shell. 

There are two types of pairs of electrons, ones that are being used in a bond, known as bonding pairs, and ones that aren’t shared, known as a lone pair. 

Lone pair: a pair of electrons in the outer shell not used in bonding. 

Mostly, covalent bonds are formed by each bonding atom donating one electron. In some cases, one atom donates both electrons to the bond. This is known as a dative covalent or coordinate bond. 

Dative covalent (coordinate) bond: a bond formed by a shared pair of electrons which has been donated by one of the bonding atoms only. It can be written as A—>B, with the arrow indicating the direction in which the electron pair has been donated.

Some substances may be a mix of covalent and ionic bonding, like MgCO₃:

There are two kinds of covalent structure: simple molecular and giant covalent lattice. 

Simple molecular: a 3 dimensional structure of molecules, held together by weak intermolecular forces 

  • Simple molecular structures have low boiling points, because the intermolecular forces are van der Waals’ forces and relatively weak, so little energy is needed to overcome them. 
  • They don’t conduct electricity because there are no charged particles that are free to move
  • They are soluble in non-polar solvents, because van der Waals’ forces form between the simple molecular structure and the non-polar solvent. 

Giant covalent lattice: a 3 dimensional structure of atoms, bonded together by strong covalent bonds

  • They have high melting and boiling points because the strong covalent bonds between the atoms require a high amount of energy to overcome
  • They don’t conduct electricity (apart from graphite) because there are no charged particles free to move
  • They’re insoluble in both polar and non-polar solvents because the covalent bonds are too strong to be overcome. 

Diamond and graphite are two allotropes of carbon.

Allotrope: two or more different forms in which an element can exist

Diamond:

  • has a tetrahedral structure held together by covalent bonds
  • it’s not an electrical conductor because there are no delocalised electrons to carry charge; all the outer-shell electrons are used to form bonds
  • it’s hard because the tetrahedral structure allows external forces to be spread throughout the lattice. 

Graphite:

  • has strong hexagonal layers, covalently bonded, with weak van der Waals’ forces between them 
  • it conducts electricity because there are delocalised electrons between the layers, that can move parallel to them and carry a charge
  • it’s soft because the bonding within each layer is strong, but the forces between each layer are weak and allow them to slide easily. 

Metallic bonding: the electrostatic attraction between a lattice of positive ions and a sea of delocalised electrons. 

Metallic substances don’t bond covalently or ionically, and this gives them different properties to ionic or covalent substances:

  • High melting/boiling points: there’s strong electrostatic attraction between the positive lattice and negative sea, that requires a lot of energy to overcome
  • They conduct electricity well: thanks to the sea of delocalised electrons, which can move and carry a charge. When molten, the ions can move too. 
  • They’re insoluble in water or non-polar substances because the electrostatic attraction is too strong for the interactions with the solvents to overcome

Russian Vocabulary: Chemistry

Originally posted by labphoto

In honor of @polysprachig ‘s  February Challenge for Science & Technology, as well as my college minor, here is a vocab list. It is a bit extensive but not too much that you need to be a chem major to understand.

Хи́мия - Chemistry

а́том [m] - atom
газ [m] - gas
жи́дкость [f] - liquid
кислота́ [f] - acid
моле́кула [f] - molecule
моль [m] - mole
нейтро́н  [m] - neutron
осно́ва [f] - base
прото́н [m] - proton
соста́в [m] - compound
состоя́ние вещества́ - state of matter
твёрдый – solid (adj.)
хими́ческая реа́кция [f] - chemical reaction
электро́н [m] - electron
элеме́нт [m] - element
ядро́ [n] – nucleus
раство́р [m] - solution
раствори́тель [m] - solvent
растворённое вещество́ [n] - solute

Неоргани́ческая хи́мия - Inorganic Chemistry

ио́нная связь [f] - ionic bond
ковале́нтная связь [f] - covalent bond
актини́ды [pl] - actinides
анио́н [m] - anion
лантано́иды [pl] - lanthanides
мета́лл [m] - metal
полумета́ллы [pl] - metalloid
полупроводни́к [m] - semiconductor
немета́лл [m] - non-metal
благоро́дные газы [pl] - noble gases
ио́н [m] - ion
иониза́ция [f] - ionization
катио́н [m] - cation
щелочны́е мета́ллы [pl] - alkali metals
щёлочноземельные мета́ллы [pl] - alkaline earth metals

Органи́ческая хи́мия - Organic Chemistry

аминокислота́ [f] - amino acid
бело́к [m] - protein
биохи́мия [f] - biochemistry
водоро́дная связь [f] - hydrogen bond
ДНК (дезоксирибонуклеи́новая кислота́) - DNA
жи́рная кислота́ [f] - fatty acid
крахма́л 
[m] - starch
липи́д [m] - lipid
мономе́р [m] - monomer
насы́щенный жир [m] - saturated fat
ненасы́щенный жир [m] - unsaturated fat
нуклеи́новая кислота́ [f] - nucleic acid
нуклеоти́д
 [m] - nucleotide
полиме́р [m] - polymer
РНК (рибонуклеи́новая кислота́) - RNA
углево́д [m] - carbohydrate
функциона́льная гру́ппа [f] - functional group

Физи́ческая хи́мия – Physical Chemistry

катализа́тор [m] - catalyst
радиа́ция
[f] - radiation
ра́диоакти́вный распа́д [m] - radioactive decay
теплопрово́дность [f] - thermal conductivity
энтальпи́я[f] - enthalpy
термодина́мика[f] - thermodynamics
термохи́мия [f] - thermochemistry

–> Link to Quizlet set: Here <–

Proteins

We’ve talked about amino acids before, but this is where they get interesting. Amino acids combine to make up proteins: proteins are polymers and amino acids are its monomers. There are twenty amino acids, which would be useful to memorise if you’re continuing with biology. At pH 7, ten are non-polar and uncharged, five are polar and uncharged, three are polar and charged positive, and two are polar and charged negative. This is a handy table:

(Source: Pearson Ed via University of Illinois at Chicago)

These amino acids have structures that generally look like this:

The “R” group is a specific side chain that varies among the amino acids, making each one unique–and hence determines their charge.

Amino acids joined together through a dehydration reaction, where a water molecule is formed and removed to form a covalent bond called a peptide bond. A structure resulting from a bunch of these bonds repeating over and over is called a polypeptide. Like DNA molecules, polypeptides have a direction: they’ve got an amino acid at one end (the N-terminus) and a carboxyl group at the other (the C-terminus).

Proteins are polypeptides, accounting for 50% of dry mass in almost all cells. They’re incredibly diverse, and are instrumental in almost everything that organisms do, so it’s only natural that there must be a whole lot of different types—enzymatic proteins which accelerate chemical reactions, receptor proteins which respond to chemical stimuli, defensive proteins that protect against disease… And that just scratches the surface.

Protein function is dictated by structure, and proteins structures are hierarchical in nature—there are four different levels:

  1. Primary: This is the amino acid sequence. There are twenty types of amino acids, and proteins are chains of 127 of them, so there are thousands of different combinations. The particular sequence of amino acids is determined by genetic information, so essentially, DNA dictates how proteins are built.
  2. Secondary: This is the way the amino acids are folded into regular units. These are the result of hydrogen bonds between the backbones of the amino acid and carboxyl groups. These bonds are usually formed to keep non-polar parts away from water. There are two main types: alpha helix and beta pleated sheet.
  3. Tertiary: The overall 3D way the polypeptide folds up. This is the result from the interactions between the side chains (R groups) of the amino acids, and the whole tertiary structure is held together by a bunch of different forces, such as hydrogen bonding, weak dispersive forces, and disulphide bonds.
  4. Quaternary: Some proteins stop at the tertiary structure, but others go further, joining up a bunch of 3D units to form a larger functional molecule, held together by weak interactions like the forces listed above.

The kind of structure a protein has fully determines what function it serves. The structure depends on a variety of different conditions—if the chemical and physical environment, pH, salt concentration or temperature change, the protein structure might unravel and denature, and thus become unable to perform its function.

Body images sourced from Wikimedia Commons

Further resources: Video to get your head around the levels of structure and another about function