Periodic Law and Trends

Vocabulary practice flashcards covering the organization of the periodic table, types and properties of elements, periodic law, blocks, and periodic trends including atomic radius, ionization energy, electron affinity, ionic radii, and electronegativity.

Metals

Elements that are good conductors of heat and electricity.

Nonmetals

Elements that are poor conductors of heat and electricity.

Metalloids

Elements that have characteristics of both metals and nonmetals.

Malleable

A property of metals meaning they can be hammered or rolled into thin sheets.

Ductile

A property of metals meaning they can be drawn into fine wires.

Tensile strength

The property of a metal that resists breaking when pulled.

Conductibility

The ability of metals to conduct electricity, heat, etc.

Dmitri Mendeleev

Scientist who developed the first periodic table by organizing the elements according to their atomic masses.

Henry Moseley

Scientist who arranged the elements in the periodic table according to increasing atomic number.

Groups

The $18$ vertical columns of elements with similar properties.

Periods

The horizontal rows found in the periodic table.

Periodic Law

The principle stating that the physical and chemical properties of the elements are periodic functions of their atomic number.

The Lanthanides

The $14$ elements with atomic numbers from $58$ to $71$.

The Actinides

The $14$ elements with atomic numbers from $90$ to $103$.

Group 1 Alkali Metals

Elements in the s-block that are soft enough to cut with a knife and very reactive.

Group 2 Alkaline Earth Metals

Elements in the s-block that are slightly less reactive than Group 1 metals.

Transition Elements

Groups $3\text{--}12$ d-block elements with $2$ valence electrons, characterized as metals with typical metallic properties.

Halogens

Group $17$ p-block elements with $7$ valence electrons that are the most reactive nonmetals.

Noble Gases

Group $18$ p-block elements that have a full set of valence electrons ($8$ valence electrons) and are inert (nonreactive).

Main Group Elements

The elements belonging to the s-block and p-block of the periodic table.

f-Block Elements

The block of elements on the periodic table consisting of the Lanthanides and Actinides.

Octet Rule

Atoms tend to gain, lose or share electrons in order to acquire a full set of $8$ electrons.

Atomic Radius

One-half the distance between the nuclei of identical atoms that are bonded together.

Atomic Radius (Group Trend)

Atoms get larger going down a group as orbitals and electrons are added.

Atomic Radius (Period Trend)

Atoms get smaller from left to right across periods due to increasing attractive forces between additional protons and electrons.

Ion

An atom or group of bonded atoms that has a positive or negative charge.

Ionization

Any process that results in the formation of an ion.

Ionization Energy ($IE$)

The energy required to remove one electron from a neutral atom.

Ionization Energy (Group Trend)

Ionization energies decrease as you go down a group due to the electrons being farther from the nucleus.

Ionization Energy (Period Trend)

Ionization energies increase as you go from left to right across a period because electrons are held more strongly by smaller atoms.

Electron Affinity

The energy change that occurs when an electron is acquired by a neutral atom.

Negative Electron Affinity Value

Indicates that energy is released when an electron is gained by an atom.

Cation

A positive ion that is smaller than its neutral atom.

Anion

A negative ion that is larger than its neutral atom.

Electronegativity

A measure of the ability of an atom in a chemical compound to attract electrons from another atom in the compound.

Electronegativity Trends

Increases from left to right across a period and decreases down a group.