Question

Atoms have electrostatic attraction:
Atoms bond together:

Answer 1

Atoms have electrostatic attraction:
- Protons in one atom attract electrons in another (and opposite charges attract), so opposite or partial charges on different atoms experience Coulomb (electrostatic) forces.

Atoms bond together:
- Because forming a bonded arrangement lowers the overall energy (electrostatic attractions outweigh repulsions), atoms stick together in specific ways. Common bond types:
- Ionic bond — one atom donates one or more electrons to another, producing oppositely charged ions that attract by Coulomb forces (e.g., Na+ and Cl− in NaCl).
- Covalent bond — atoms share one or more pairs of electrons so each nucleus is attracted to the shared electrons; orbital overlap and quantum exchange effects stabilize the pair (e.g., H–H, C–H).
- Metallic bond — many atoms share a “sea” of delocalized electrons that electrostatically bind the positively charged metal ions in a lattice (gives conductivity and malleability).
- Polar/noncovalent interactions — partial charges on polar molecules produce dipole–dipole attraction; hydrogen bonding is a strong special case (important in water, DNA).
- Dispersion (London) forces — instantaneous fluctuations in electron density produce temporary dipoles that attract other atoms/molecules (important in noble gases and nonpolar molecules).

Underlying idea: electrostatic forces (plus quantum mechanics and the Pauli exclusion principle) determine the balance of attractions and repulsions and thus which bonds form and how strong they are.