APHY 101 Ch. 2 Terms Flashcards
Chemistry
Considers the composition of substances and how they change.
Biochemistry
A branch of science dealing with the chemistry of life forms.
Matter
Anything that has weight and takes up space (solids, liquids, and gasses).
Mass
Refers to the amount of a substance.
Weight
Refers to how heavy something is.
Elements
Simplest example of matter with specific chemical properties. Most elements occur naturally and others are artificially made (refer to periodic table for examples)
Compounds
Elements that are are more commonly parts of chemical combinations.
Bulk Elements
Elements required in large amounts (carbon, hydrogen, oxygen, nitrogen, sulfur and phosphorus - these make up more than 95% of the human body).
Trace Elements
Elements required in small amounts (important parts of enzymes).
Ultratrace Elements
Elements that are normally toxic in large amounts, but are vital in very small amounts.
Atom
The smallest particle of an element that has the properties of that element.
Chemical Bonds
Atoms that can combine with atoms like themselves or with other atoms by forming attractions.
Electron
Extremely small particle within an atom: almost no weight; carries a negative electrical charge and is in constant motion around an atomic nucleus.
Proton
Relatively large particle within an atom; carries a positive electrical charge and is found within an atomic nucleus.
Neutron
Relatively large particle within an atom; about the same weight as a proton; uncharged and thus electrically neutral; found within an atomic nucleus.
Ion
A particle, formed from an atom, that is electrically charged because it has gained or lost one or more electrons.
Molecule
A particle formed by the chemical union of two or more atoms.
Atomic Number
The number of protons in the atoms of a particular element.
Atomic
The number of protons plus the number of neutrons in each of an elements atoms.
Isotope
Atoms that have the same atomic number but different in atomic weight.
Radioactive
Isotopes of an element that have unstable atomic nuclei that decompose and release energy until they reach a stable form.
Atomic Radiation
The energy fragments that are emitted from unstable isotopes. Includes three types: alpha, beta, and gamma.
Alpha Radiation
Particles from atomic nuclei, each of which includes two protons and two neutrons, that move slowly and cannot easily penetrate matter.
Beta Radiation
Smaller particles (electrons) that travel faster and more. deeply penetrate matter.