22 terms

Periodic Table Vocabulary

Here is a set of cards that will help with the terms from the Periodic Table unit.
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Alkali metals
Group 1 elements: most reactive and least dense metals.
Alkaline Earth metals
Group 2 elements: less reactive, more dense metals that form solutions in water that have a pH greater than 7.
Transition Elements
Groups 3-12 elements: metals that are more dense and less reactive than groups 1 & 2; they also can varying numbers of electrons in their outer most level.
Halogens
Group 17 elements: these are the most reactive nonmetals, and are always found in a combined state.
Noble Gases
Group 18 elements: once known as "inert" these elements are considered stable because they have a full set of outer level electrons.
Metals
Composed a majority of the elements on the periodic table; they conduct electricity, have luster, are malleable and ductile.
Nonmetals
Most of these elements are gases at room temperature, but some are solids which do not conduct electricity, and are considered to be dull in appearance.
Metalloids
These elements, such as boron and silicon, have properties of both metals and nonmetals.
Group/Family
A vertical column in the periodic table.
Period/Series
A horizontal row in the periodic table.
Dmitri Mendeleev
The Russian chemist credited with developing the first periodic table, with the elements in order of atomic mass.
Henry Moseley
The English physicist who developed the modern periodic table by putting the elements in order of atomic number.
Periodic Law
The principle that states that the properties of the elements repeat themselves at regular intervals.
Atomic Radius
Defined as one half the distance between two unbonded atoms.
Ionization Energy
The energy needed to REMOVE an electron from a gaseous atom.
Electron Affinity
The change in energy that occurs when an atom gains an electron.
Electronegativity
The ability of an atom to attract electrons, within a covalent bond, to itself.
Down - increases / Left -> right - decreases
Metallic Character & Atomic Radius
Down - decreases / Left -> right - increases
Ionization Energy, Electron Affinity & Electronegativity
Shielding Effect
The apparent reduction in the attraction of the nucleus on outer level electrons due to the blocking of inner level electrons.
Reasons why atomic radius increases
The addition of another energy level as you go down, as well as the increase in the shielding effect.
Reasons why atomic radius decreases
The addition of a proton in the nucleus causes the nucleus to become "more" positive, thus stronger, and it can pull electrons closer to itself.