Chapter 4 Vocab Flashcards
Atomic Mass
is the mass of an atomic particle, sub-atomic particle, or molecule
Atom
the smallest unit of matter that defines the chemical elements
Atomic Mass Unit
a unit of mass used to express atomic and molecular weights
Atomic Number
the number of protons in the nucleus of an atom, which determines the chemical properties of an element and its place in the periodic table
Cathode Ray
a beam of electrons emitted from the cathode of a high-vacuum tube
Dalton’s Atomic Theory
1) All matter is made of atoms. Atoms are indivisible and indestructible. 2) All atoms of a given element are identical in mass and properties. 3) Compounds are formed by a combination of two or more different kinds of atoms.
Electron
a stable subatomic particle with a charge of negative electricity, found in all atoms and acting as the primary carrier of electricity in solids
Group
is a column of elements in the periodic table of the chemical elements
Isotope
each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, and hence differ in relative atomic mass but not in chemical properties; in particular, a radioactive form of an element
Mass Number
the total number of protons and neutrons in a nucleus
Neutrons
a specialized cell transmitting nerve impulses; a nerve cell
Nucleus
the central and most important part of an object, movement, or group, forming the basis for its activity and growth
Period
a length or portion of time
Periodic Table
a table of the chemical elements arranged in order of atomic number, usually in rows, so that elements with similar atomic structure (and hence similar chemical properties) appear in vertical columns
Protons
a stable subatomic particle occurring in all atomic nuclei, with a positive electric charge equal in magnitude to that of an electron, but of opposite sign
