BiO

Atom bonding In chemistry, polarity is a separation of electric charge leading to a molecule or its chemical groups having an electric dipole moment, with a negatively charged end and a positively charged end. A water molecule, a commonly used example of polarity. Two charges are present with a negative charge in the middle (red shade), and a positive charge at the ends (blue shade). Polar molecules must contain one or more polar bonds due to a difference in electronegativity between the bonded atoms. Molecules containing polar bonds have no molecular polarity if the bond dipoles cancel each other out by symmetry. Polar molecules interact through dipole-dipole intermolecular forces and hydrogen bonds. Polarity underlies a number of physical properties including surface tension, solubility, and melting and boiling points. Atoms decay in humans through radioactive decay, where unstable atoms with an imbalance of protons and neutrons spontaneously emit high-energy particles or waves, known as ionizing radiation. This radiation can damage human tissues and DNA by ejecting electrons from other atoms, a process called ionization. While this decay happens naturally from both external sources and internal radioisotopes like potassium-40, the human body contains mechanisms to repair some of the resulting damage.  
https://www.youtube.com/watch?v=azI-_S6g8C8
Why do atoms form molecules? The quantum physics of chemical bonds explained
https://www.youtube.com/watch?v=I0GhhWbm-2k
atomic bonding
https://www.youtube.com/watch?v=Hah4gvA4Qi8
Atomic Structure and Chemical Bonding Review