Achieve Mastery of Medical Concepts

Study for medical school and boards with Lecturio

Chemical Bonding: Intramolecular and Intermolecular Bonds

In general, it is possible to distinguish between intramolecular and intermolecular bonds. The first group includes the ionic bond, atomic bond, and metallic bond. The second one includes the Van-der-Waals-bond and hydrogen bridges. These bonds have an important influence on the substance properties, such as solubility.

Last updated: 7 Mar, 2022

Editorial responsibility: Stanley Oiseth, Lindsay Jones, Evelin Maza

Intramolecular Bonds

Ionic bonding

Ionic bonding is a type of chemical bond that is based on the force of attraction between oppositely-charged ions (Coulomb-force, electrostatic force). Due to the ionic bond, there occurs a regular Regular Insulin arrangement of ions, which is also called ionic crystal. If a solid is built up by ions, then it is considered a salt. They are weaker and less stable but still abide by the octet rule. Common table salt (NaCl) is formed by ionic bonds.

  • First ions are formed when the ions are attracted by their opposite charge.
  • Sodium Sodium A member of the alkali group of metals. It has the atomic symbol na, atomic number 11, and atomic weight 23. Hyponatremia (Na) has 1 valence electron — could lose 1 (easy) or gain 7 (difficult).
  • Chlorine ( CI CI The percentage of the chest diameter occupied by the heart. Imaging of the Heart and Great Vessels) has 7 valence electrons — could gain 1 (easy) or lose 7 (difficult).
  • CI CI The percentage of the chest diameter occupied by the heart. Imaging of the Heart and Great Vessels steals the electron from Na to satisfy the octet rule — resulting in ions.
  • CI CI The percentage of the chest diameter occupied by the heart. Imaging of the Heart and Great Vessels– is now attracted to Na+.
  • This will come apart in water.

The following are the common characteristics of an ionic crystal:

  • Regular Regular Insulin, grid-like, spatial arrangement
  • Positively-charged metal ions and negatively charged non-metal ions
  • Strong forces of attraction
  • Relatively high melting and boiling temperature
  • Brittle
  • No electrical conductivity of the solid
  • Good electrical conductivity of the molten, and of the aqueous solution

Atomic bond (covalent bond)

An atomic bond is a type of chemical bond that is based on the formation of a common electron pair. The atoms have solid partners, referring to a directed binding. Single covalent bonds involve the sharing of one pair of electrons. Hydrogen has a valence of 1 & 1 valence electron; 2 electrons in the valence shell will satisfy the octet rule. Each has 2 electrons in the valence shell.

Single covalent bond

Single covalent bond

Image by Lecturio.

Double covalent bonds involve the sharing of two pairs of electrons (stronger). Oxygen has 6 valence electrons. It needs 2 more electrons to satisfy the octet rule. It shares 2 electrons with another oxygen. They have 2 pairs of shared electrons in this bond. The substance class of molecular substances can be derived from this type of binding.

Substance properties: Relatively low melting and boiling temperature.

Double covalent bond

Double covalent bond:
They have 2 pairs of shared electrons in this bond. Each oxygen has 8 electrons in the valence shell (stable).

Image by Lecturio.

Metallic bond

The metallic bond is a type of chemical bond that is based on the forces of attraction between positively charged metal ions and negatively charged, versatile ions. The substance class can be derived from this binding type.

Characteristics: regular Regular Insulin, a grid-like arrangement of the positively charged metal ions in a space

Substance properties:

  • Mostly solid (except mercury Mercury A silver metallic element that exists as a liquid at room temperature. It has the atomic symbol Hg (from hydrargyrum, liquid silver), atomic number 80, and atomic weight 200. 59. Mercury is used in many industrial applications and its salts have been employed therapeutically as purgatives, antisyphilitics, disinfectants, and astringents. It can be absorbed through the skin and mucous membranes which leads to mercury poisoning. Because of its toxicity, the clinical use of mercury and mercurials is diminishing. Renal Tubular Acidosis)
  • Metallic lustre
  • Good electrical conductivity (which decreases with an increase in the temperature)
  • Good thermal conductivity
  • Plastically deformable

Calculation: Not calculable, as it occurs in metals and alloys

Hydrogen bonds

Hydrogen bonds form between polar molecules:

  • Slight negative charge by the oxygen of H2O
  • Slight positive charge by the hydrogens
  • Causes attraction between them
Hydrogen bonds

Hydrogen bonds

Image by Lecturio.

Intermolecular Bonds

Van-der-Waals-bond

The Van-der-Waals forces represent weak forces of attraction or non-covalent interactions between molecules, atoms or ions. It is dependent on the particular size and the contact surface.

Hydrogen bridges

If two molecules interact via a hydrogen atom, then so-called hydrogen bridges occur. Strong forces of attraction are formed between the positively charged hydrogen atom, and a free electron pair of a nitrogen Nitrogen An element with the atomic symbol n, atomic number 7, and atomic weight [14. 00643; 14. 00728]. Nitrogen exists as a diatomic gas and makes up about 78% of the earth’s atmosphere by volume. It is a constituent of proteins and nucleic acids and found in all living cells. Urea Cycle, oxygen, or fluorine atom. Hydrogen bridges are only formed with the most electronegative elements (N, O, and F). At this, there is a donator and an acceptor.

In the case of the donor, the hydrogen atom is bonded to a highly electronegative partner, whereby the hydrogen atom becomes the positive pole (positive partial charge) and the binding partner becomes the negative pole. The acceptors are generally covalently bonded nitrogen Nitrogen An element with the atomic symbol n, atomic number 7, and atomic weight [14. 00643; 14. 00728]. Nitrogen exists as a diatomic gas and makes up about 78% of the earth’s atmosphere by volume. It is a constituent of proteins and nucleic acids and found in all living cells. Urea Cycle, oxygen, or fluorine atoms, which possess a negative partial charge.

The relevance of the hydrogen bridges in the biochemistry:

  • DNA DNA A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine). DNA Types and Structure: Base pairing, an amalgamation of the DNA DNA A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine). DNA Types and Structure strands
  • RNA RNA A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. RNA Types and Structure:  tRNA tRNA The small RNA molecules, 73-80 nucleotides long, that function during translation (translation, genetic) to align amino acids at the ribosomes in a sequence determined by the mRNA (RNA, messenger). There are about 30 different transfer rnas. Each recognizes a specific codon set on the mRNA through its own anticodon and as aminoacyl trnas (RNA, transfer, amino Acyl), each carries a specific amino acid to the ribosome to add to the elongating peptide chains. RNA Types and Structure (formation of intramolecular hydrogen bridges)
  • Proteins Proteins Linear polypeptides that are synthesized on ribosomes and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of amino acids determines the shape the polypeptide will take, during protein folding, and the function of the protein. Energy Homeostasis: Formation of secondary structures (α-helix, β-sheet)

Other Sigma Bonds

Sigma bonds

Sigma bonds are types of bonds in a molecular structure that are formed by end-to-end overlap of atomic orbitals. Unless this type of overlap is possible, a sigma bond may not form. One simple sigma bond is the one present in an H2 molecule. Since an H atom only has an s-orbital, the overlap will be between two s-orbitals.

Overlap between two p-orbitals is also possible. To form a sigma bond, the interaction should be a head-to-tail interaction, which is one lobe of one p-orbital faces one lobe of the other p-orbital, enabling the overlap as in the figure below.

Sigma bonds may also be formed by the interaction of dissimilar orbitals. In the case of the bond between Hydrogen and Fluorine in hydrogen fluoride Fluoride Inorganic salts of hydrofluoric acid, hf, in which the fluorine atom is in the -1 oxidation state. Sodium and stannous salts are commonly used in dentifrices. Trace Elements, the H atom only has an s-orbital available for bonding, while the F atom has a p-orbital. Even though the two orbitals are different, a sigma bond may still be formed as long as the two interacting orbitals are in the correct orientation Orientation Awareness of oneself in relation to time, place and person. Psychiatric Assessment. In this way, sharing of electrons will be achieved between the two atoms.

For example, if the s and p-orbital interacting with each other are in an orientation Orientation Awareness of oneself in relation to time, place and person. Psychiatric Assessment where one of the lobes of the p-orbital is directly facing the s-orbital, a sigma bond may form because overlap of orbitals is possible. If the s-orbital of the H atom is not directly facing any of the two lobes of the p-orbital, no sigma bond will be formed because orbital overlap will not occur.

Sigma bonds

Sigma bonds:
Sigma (σ) bonds form from the overlap of the following: (a) two s orbitals, (b) an s orbital and a p orbital, and (c) two p orbitals. The dots indicate the locations of the nuclei.

Image: “Sigma (σ) bonds form from the overlap of the following” by OpenStax College. License: CC BY 4.0

Hybridization Hybridization The genetic process of crossbreeding between genetically dissimilar parents to produce a hybrid. Blotting Techniques

For heteroatomic molecules, the overlap of simple s and p-orbitals will result in a highly restricted molecular structure. For example, the compound methane does not follow an ordinary square planar structure; instead, it follows a tetrahedral configuration. Also, since the p-orbitals are oriented in different planes, this would involve different energy values. To aid this, hybridization Hybridization The genetic process of crossbreeding between genetically dissimilar parents to produce a hybrid. Blotting Techniques should occur. Orbital hybridization Hybridization The genetic process of crossbreeding between genetically dissimilar parents to produce a hybrid. Blotting Techniques is the mixing of atomic orbitals into new hybrid orbitals, with different shapes and energies to the component atomic orbital, suitable for electron pairing during the formation of covalent bonds.

In a methane molecule, it is not possible to form four sigma bonds due to 1 s-s and 3 s-p interaction. This is because they will have different amounts of energy involved. What happens then is the one s and the 3 p-orbitals of the C atom will be hybridized to form 4 sp3 hybrid orbitals that are all similar in energies and shapes. Each of these sp3-orbitals will overlap with the s-orbital of an H atom forming four sigma bonds, resulting in a tetrahedral configuration.

Different types of hybrid orbitals may be formed, depending on the type of atomic orbitals that combine. If one s and one p-orbital are mixed, two sp hybrid orbitals are formed. On the other hand Hand The hand constitutes the distal part of the upper limb and provides the fine, precise movements needed in activities of daily living. It consists of 5 metacarpal bones and 14 phalanges, as well as numerous muscles innervated by the median and ulnar nerves. Hand: Anatomy, if one s and two p orbitals are mixed, three sp2-orbitals are formed. The number of hybrid orbitals corresponds to the number of sigma bonds that the atom can form. For example, if an atom has two sp hybridized orbitals, this means it can form two sigma bonds. The same case is if an atom has three sp2 hybridized orbitals, three sigma bonds can be formed.

Orbital hybridisation

Orbital hybridisation sp3

Image: “Orbital hybridisation sp3” by Jfmelero. License: CC BY-SA 3.0

Pi bond

Between two atoms, only one single bond is possible to be formed. This is because there is only one way for end-to-end interaction to occur, especially since the p orbitals are oriented in different planes. Another type of orbital overlap is possible. If two p-orbitals are oriented parallel to each other, a side-by-side overlap is possible. This type of interaction leads to the formation of pi bonds.

Pi bonds are weaker than sigma bonds because of the weaker overlap between the orbitals. Electrons in pi bonds can also be referred to as pi electrons. Pi bonds are present in multiple bonds (double or triple bonds). Pi interaction is only possible between atoms that are already sigma bonded.

In the case of the compound ethene, three sigma bonds are formed by each of the C atoms. This means that 3 hybrid orbitals were used. This is only possible if 1 s and 2p-orbitals have undergone hybridization Hybridization The genetic process of crossbreeding between genetically dissimilar parents to produce a hybrid. Blotting Techniques. This means each of the C atoms will have an extra p-orbital that can overlap with the p-orbital of the other C atom to form a pi bond.

Pi bond

Pi bonds:
Pi (π) bonds form from the side-by-side overlap of two p-orbitals. The dots indicate the location of the nuclei.

Image: “Pi (π) bonds form from the side-by-side overlap of two p-orbitals” by OpenStax College. License: CC BY 4.0

Double and triple bond

Double bonds and Triple bonds only differ in the number of pi bonds present in the bond. A double bond will contain one sigma bond and one pi bond, while a triple bond contains one sigma bond and two pi bonds.

There is a correlation Correlation Determination of whether or not two variables are correlated. This means to study whether an increase or decrease in one variable corresponds to an increase or decrease in the other variable. Causality, Validity, and Reliability between the type of hybrid orbital and the type of bond present around an atom. A carbon compound with the C atom containing 4 sp3-orbitals can form 4 sigma bonds. A carbon compound with the C atom containing 3 sp2-orbitals and one p can form 3 sigma bonds and 1 pi bond. A carbon with the C atom containing 2 sp-orbitals and 2 p-orbitals can form 2 sigma bonds and 2 pi bonds. This leads to the formation of double and triple bonds.

References

  1. Burdge, Julia & Overby Jason (2012). Chemistry Atoms First. USA: McGraw-Hill Companies, Inc.
  2. Chang, R. (2010). Chemistry. 10th ed. McGraw-Hill International. USA.

USMLE™ is a joint program of the Federation of State Medical Boards (FSMB®) and National Board of Medical Examiners (NBME®). MCAT is a registered trademark of the Association of American Medical Colleges (AAMC). NCLEX®, NCLEX-RN®, and NCLEX-PN® are registered trademarks of the National Council of State Boards of Nursing, Inc (NCSBN®). None of the trademark holders are endorsed by nor affiliated with Lecturio.

Study on the Go

Lecturio Medical complements your studies with evidence-based learning strategies, video lectures, quiz questions, and more – all combined in one easy-to-use resource.

Learn even more with Lecturio:

Complement your med school studies with Lecturio’s all-in-one study companion, delivered with evidence-based learning strategies.

User Reviews

¡Hola!

Esta página está disponible en Español.

🍪 Lecturio is using cookies to improve your user experience. By continuing use of our service you agree upon our Data Privacy Statement.

Details