the center of an atom that contains most of the mass of the atom in the form of positive protons and negative neutrons
The positively charged (+) particle in the nucleus which determines what element this is an atom of. Example: 1 Proton is the element Hydrogen.
Russian scientist who discovered a logical pattern in the properties of the elements
the average mass of one atom of the element. The mass averages the common form and the isotopes. It is equal to the mass of the protons and the neutrons.
a description of how easily and quickly an element combines with other elements and compounds
a type of element that has some of the characteristics of metals and some of the characteristics of nonmetals
made of one kind of matter and has definite properties, may be a single element or a compound
the "smallest piece of matter" that if broken into smaller pieces, loses its original properties
the electrons in energy level that is farthest from the nucleus; that helps determine which elements atom will bond with.
An atom with the same number of protons and a different number of neutrons from other atoms of the same element
an atom that has taken on or lost electrons to become negatively or positively charged instead of neutral