COVID-19 Awareness and Hybrid Orbitals

COVID-19 Awareness

• COVID-19 is caused by SARS-CoV-2
• It spreads easily between people
• Signs and symptoms include fever, chills, cough, breathing difficulties, headaches, diarrhea, loss of taste/smell, and other nonspecific symptoms.
• Transmission occurs via respiratory droplets, airborne particles, and contaminated surfaces.
• Prevention involves using both pharmaceutical and non-pharmaceutical measures.
• Pharmaceutical measures include safe and effective vaccines.
• Non-pharmaceutical measures include respiratory hygiene (masks, cough etiquette), hand hygiene (frequent handwashing/sanitizing), social distancing, and avoiding crowded/poorly ventilated spaces.
• Safety protocols are crucial due to the virus's evolving nature.

Hybrid Orbitals

• Carbon's valence shell electron configuration: 2s², 2px¹, 2py¹, 2pz¹
• Carbon forms four equivalent bonds in methane and tetrachloride
• The tetrahedral structure of methane and carbon tetrachloride display that carbon forms four equivalent bonds - leading to an octet configuration.
• The 2s and three 2p orbitals hybridize to form four sp³ hybrid orbitals.
• These orbitals are tetrahedrally oriented.
• The four covalent bonds in methane involve shared electron pairs with four hydrogen atoms, forming a tetrahedral shape.

sp² Hybrid Orbitals

• Carbon atoms with double bonds employ sp² hybridization.
• Three sp² hybrid orbitals are formed.
• One p-orbital remains unhybridized.
• The sp² orbitals are involved in bonding and forming sigma bonds.
• The unhybridized p orbitals form pi bonds.

sp Hybrid Orbitals

• Carbon atoms with triple bonds utilize sp hybridization.
• Two sp hybrid orbitals are created
• Two p-orbitals are left unhybridized.
• sp hybrid orbitals are involved in sigma bond formation.
• The two unhybridized p orbitals form two pi bonds

Alkenes and Alkynes

• Alkenes: Compounds containing a carbon-carbon double bond (CnH2n).
• Alkynes: Compounds containing a carbon-carbon triple bond (CnH2n-2).
• The double or triple bond is the source of their reactivity and are stronger than single carbon-carbon bonds.
• Alkenes show cis-trans isomerism.
• Sequential double bonds/single bonds can exhibit increased resonance stability (conjugation).
• Types for alkenes and alkynes are presented - structural examples provided

Properties of Alkenes

• Alkenes, although nonpolar, have greater solubility in water than alkanes. This is due to slight interaction with water from their exposed pi electrons
• Physical properties (e.g., boiling points) are similar to those of corresponding alkanes

Preparation of Alkenes

• Alkenes are prepared via elimination reactions from alcohols and halides (1°, 2°, 3°).

Addition Reactions (Alkenes)

• Addition reactions (alkene) have the general form: C=C + AB → C-C
• Reagents add to pi-bonds, and hybridization occurs
• No atoms are lost

Reactions of Alkenes and Alkynes

• Examples and mechanisms are provided for addition of various reagents such as hydrogen (H2), halogens (X2), hydrogen halides (HX), and water (H2O).
• Markovnikov's rule governs the addition of hydrogen halides to unsymmetrical alkenes.
• Anti-Markovnikov addition reactions are illustrated as well.
• Important reactions such as hydrogenation and oxidation are included

Benzene

• Benzene is a cyclic, conjugated compound with delocalized pi electrons.
• Benzene demonstrates aromaticity.

Alkynes

• Alkynes are hydrocarbons with one or more triple bonds between carbon atoms.
• Includes the reaction mechanism and some examples and structures are provided.
• Terminal alkynes can form acetylide anions.
• Alkynes exhibit reactivity under various conditions

Synthetic Drugs

• Some synthetic drugs contain alkynes.
• These compounds aren't naturally occurring but are synthesized by chemists.

Properties of Alkynes

• Terminal alkynes are weaker acids than water, but they can lose the hydrogen from terminal triple bind to strong bases.
• Their physical properties, similar to alkanes and alkenes lack H-bonding, have weak intermolecular forces and are relatively low mp/bp, and are water-insoluble.
• Various synthesis methods and reactions involving alkynes are presented.