The symptoms of influenza (flu) appear suddenly and often include: 1  Fever of 100.4Â°F (38Â°C) to 104Â°F (40Â°C), which can reach 106Â°F (41Â°C) when symptoms first develop. 2  Body aches and muscle pain (often severe), commonly in the back, arms, or legs. 3  Headache. Pain when you move your eyes.
A chemical bond is an attraction between atoms that allows the formation of chemical substances that contain two or more atoms. The bond is caused by the electrostatic force of attraction between opposite charges, either between electrons and nuclei, or as the result of a dipole attraction. double bond between two atoms is formed by the sharing of two pairs of electrons, one in a sigma bond and one in a pi bond, with electron density concentrated on two opposite sides of the internuclear axis.
A chemical bond is a lasting attraction between atoms, ions or molecules that enables the formation of chemical compounds. The bond may result from the electrostatic force of attraction between oppositely charged ions as in ionic bonds; or through the sharing of electrons as in covalent bonds.