Hydrogen covalent

Figure 10-4 shows the hybridization that occurs in ethylene, H2C=CH2. Each carbon has sp2 hybridization. On each carbon, two of the hybrid orbitals overlap with an s-orbital on a hydrogen atom to form a carbon-to-hydrogen covalent bond. The third sp2 hybrid orbital overlaps with the sp2 hybrid on the other carbon to form a carbon-to-carbon covalent bond. Note that each carbon has a remaining p-orbital that has not undergone hybridization. These are also overlapping above and below a line joining the carbons. 

Was this your answer The polar oxygen-hydrogen covalent bond in each methanol molecule leads to hydrogen bonding between molecules. These relatively strong interparticle attractions hold methanol molecules together as a liquid at room temperature. 

D. a hydrogen covalently coupled to an electropositive atom and a second electronegative atom... 

Figure 4-4. The structure of FAD. Arrows indicate positions where hydrogens covalently bind when FAD is reduced to FADH2. FMN consists only of the riboflavin moiety plus one phosphate.

For a bond to be called a hydrogen bond, it must have a hydrogen covalently bonded to O, N, or F. This hydrogen then forms a hydrogen bond with another O, N, or F. 

Ethyl alcohol is not ionic, but is polar due to an hydroxyl group at one end of the molecule. Furthermore, the hydroxyl group is a hydrogen bond former (hydrogen covalently bonded to electronegative oxygen). Ethyl alcohol is soluble in water. 

The intermolecular attractive force known as hydrogen bonding can occur when a molecnle contains hydrogen covalently bound to oxygen or nitrogen. The O-H or N-H bond is highly polarized ... 

The positive value suggests that hydrogen gas should displace copper from copper(ii) salts in solution under standard conditions. In practice, the rate of reaction is so slow that the reaction is kinetically non-feasible. This is because a relatively large amount of energy is needed to break the strong hydrogen—hydrogen covalent bond before the reaction can start. 

The pair of dots represents the shared electron pair of the hydrogen-hydrogen covalent bond. For a molecule of fluorine, F2, the electron-dot notations of two fluorine atoms are combined. 

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