Chapter 4- Atoms and Elements Flashcards
The smallest identifiable unit of an element.
atom
The unit commonly used to express the masses of protons, neutrons, and nuclei.
Atomic Mass Unit (AMU)
The number of ____ in an element’s nucleus defines the element.
protons
The number of protons in the nucleus of an atom is it’s ____ ____ and is represented by the symbol ____.
atomic number, Z
Each element is represented by a unique ____ ____, a one or two letter abbreviation.
chemical symbol
Elements that tend to lose electrons in chemical reactions.
Metals
Found on the left side and center of the periodic table of elements.
Metals
Occupy the upper right hand side of the periodic table of elements.
Nonmetals
Elements that tend to gain electrons in chemical reactions
Nonmetals
Elements that lie along the zig-zag line between metals and nonmetals.
metalloids
Metalloids are sometimes called _____.
semiconductors
Groups 1A-A on the periodic table of elements
main-group elements
Elements in the middle of the periodic table whose properties tend to be less predictable based simply on their position in the periodic table.
Transition metals
Lose electrons in their chemical reactions, but do not necessarily acquire noble gas configurations
Transition metals
Transition metals (transition elements) are labeled with the letter ___.
b
Group name of the 8 A elements (chemically inert gasses)
Noble gases
Group name of the 1A elements (all very reactive)
alkali metals
Group name of the 2A elements
alkaline earth metals
Group name of the 7A elements (very reactive nonmetals)
halogens
In chemical reactions, atoms often lose or gain electrons to form charged particles called ____.
ions
ion charge = # of what - # of what
protons minus electrons
An atom or group of atoms that has gained or lost one or more electrons, so that it has an electric charge.
ion
positively charged ion
cation
negatively charged ion
anions
The number associated with the letter A above each main group column in the periodic table (1-8) gives the number of _____ _____ for the elements in that column
valence electrons
The outermost electrons in an atom
valence electrons
Helium is in column 8A but has only ___ valence electrons.
2
