What is matter?
Anything that takes up space and has mass.
What four elements make up 96% of living matter?
Oxygen (O), Carbon (C), Hydrogen (H), and Nitrogen (N).
What are trace elements?
Elements required in only minute quantities for life
What is an element?
A substance that cannot be broken down into other substances.
What is a compound?
A substance made of two or more different elements in a fixed ratio.
What are emergent properties?
New properties that arise when elements combine into compounds.
What is the smallest unit of matter?
Atoms
What are the three subatomic particles?
Protons (+), Neutrons (0), Electrons (–).
What is an isotope?
Atoms of the same element with different numbers of neutrons.
What is potential energy?
Stored energy based on position or structure.
What determines the chemical behavior of an atom?
The distribution of its electrons, especially in the valence shell.
What are valence electrons?
Electrons in the outermost shell.
What is a covalent bond?
Sharing of a pair of valence electrons between atoms.
Difference between nonpolar and polar covalent bonds?
Nonpolar: electrons shared equally. Polar: electrons shared unequally.
What is an ionic bond?
Attraction between a positively charged ion (cation) and a negatively charged ion (anion).
What is a hydrogen bond?
A weak attraction between polar molecules (e.g., water molecules).
Which bond is the strongest?
Covalent
Why is molecular shape important?
It determines a molecule’s function and interactions.
Example of molecular shape affecting function?
Morphine mimics endorphins by binding to the same brain receptors.
What is a chemical reaction?
The making and breaking of bonds, rearranging matter into new products.
Do chemical reactions create or destroy matter?
No, they only rearrange it.
What is chemical equilibrium?
When forward and reverse reactions occur at the same rate.
