Final answer:
Atoms connect via covalent bonds by sharing pairs of electrons, such as in hydrogen gas and water molecules, which is vital for molecular stability.
Step-by-step explanation:
Atoms connected by covalent bonds share pairs of electrons. A notable example is the hydrogen gas (H-H) where two hydrogen atoms each share their one electron to form a single covalent bond. This sharing of electrons is essential for molecule stability, as seen in the formation of water molecules. In water, or H2O, each hydrogen atom contributes one electron to the oxygen atom, allowing it to complete its outer electron shell, leading to a stable electronic configuration.
Covalent bonds also come in different forms such as single, double, or triple bonds based on how many pairs of electrons are shared between atoms. These strong bonds are what hold the atoms in a molecule together and are found commonly in biological molecules essential to life.