BackAnatomy & Physiology: Chemical Bonds and Atomic Structure
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Terms in this set (30)
Matter is anything that takes up space and has mass; it is made of atoms and molecules.
An element is a substance made of only one type of atom and cannot be broken down by normal means.
Hydrogen, Carbon, Nitrogen, and Oxygen are the major elements making up 96% of body mass.
An atom is the smallest unit of an element that retains its chemical properties.
Protons (+), Neutrons (neutral), and Electrons (-).
The atomic number is the number of protons in an atom's nucleus, defining the element.
The mass number is the sum of protons and neutrons in the nucleus.
Isotopes are atoms of the same element with different numbers of neutrons and thus different mass numbers.
A radioactive isotope has an unstable nucleus that decays, releasing energy that can damage cells or be used as tracers.
Valence electrons are electrons in the outermost shell that determine an atom's chemical reactivity.
The atom is inert or stable and unlikely to react chemically.
Hydrogen: 1, Oxygen: 2, Nitrogen: 3, Carbon: 4 (number of electrons needed to fill outer shell).
An ion is an atom with an unequal number of protons and electrons, giving it a charge.
Cation: positively charged ion (lost electrons). Anion: negatively charged ion (gained electrons).
An ionic bond is an electrical attraction between oppositely charged ions (cations and anions).
Water molecules separate ions, weakening ionic bonds in aqueous environments.
A covalent bond forms when atoms share valence electrons to complete their outer shells.
A molecule is two or more atoms held together by covalent bonds.
A single bond shares one pair of electrons; a double bond shares two pairs, making it stronger.
Electronegativity measures an atom's attraction for shared electrons in a covalent bond.
A covalent bond where electrons are shared equally between atoms with similar electronegativity.
A covalent bond where electrons are shared unequally, spending more time near the more electronegative atom, creating partial charges.
Regions of slight positive or negative charge due to unequal electron sharing, denoted by δ+ and δ-.
Water has polar covalent bonds; hydrogen gas, oxygen gas, and methane have nonpolar covalent bonds.
A weak electrical attraction between a partially positive hydrogen atom and a partially negative atom on another molecule or part of the same molecule.
They stabilize structures like DNA and proteins and influence water's properties essential for life.
Hydrogen bonds are about 5% as strong as covalent bonds and are easily formed and broken.
A compound is a substance made of two or more different elements chemically combined.
Water is both a molecule (held by covalent bonds) and a compound (contains hydrogen and oxygen).
Reactants are starting substances; products are substances formed by the reaction.