Definition: The role of valence electrons in chemical bonding is crucial for forming covalent and ionic bonds.

Vocabulary: Cations are positively charged ions, while anions are negatively charged ions.

Highlight: Polarity in molecules results from unequal electron sharing between atoms.

Example: Double bonds involve sharing two pairs of electrons between atoms.

Definition: Energy is defined as the ability to do work or cause change.

Example: Sunflowers demonstrate evolutionary adaptation by tolerating high concentrations of lead.

Highlight: The octet rule governs how atoms achieve stable electron configurations.

Vocabulary: Monomers are molecules that can bond together to form larger molecules.

Definition: Matter is anything that takes up space and has mass, forming the basic component of all organisms.

Highlight: CHON (Carbon, Hydrogen, Oxygen, Nitrogen) comprises 96% of living matter, demonstrating the predominance of these elements in biological systems.

Example: Table salt (NaCl) demonstrates how elements combine to form compounds with properties different from their constituent elements.

Vocabulary: Trace elements are essential elements required by organisms in minute quantities, such as zinc, copper, chromium, iodine, and boron.