Periodic Table of Elements Review

Vocabulary-style flashcards covering the laws, groups, element categories, and periodic trends of the Periodic Table.

Mendeleev’s Periodic Law

A principle stating that if the elements are arranged according to their atomic mass, a pattern can be seen in which similar properties occur regularly.

Modern Periodic Law

A principle stating that if the elements are arranged according to their atomic number, a pattern can be seen in which similar properties occur regularly.

Groups (or Families)

The vertical columns of elements in the periodic table that contain elements with similar properties.

Periods

The horizontal rows of elements in the periodic table where atomic mass and atomic number increase from left to right.

Alkali Metals

Group 1 (I) elements, such as sodium, potassium, and lithium, which have ONE valence electron, are found only as compounds in nature, and are very reactive.

Alkaline Earth Elements

Group 2 (II) elements, such as Beryllium, Magnesium, and Calcium, which have TWO valence electrons and react with water to produce basic or alkaline solutions.

Halogens

Group 17 (VII) elements that have SEVEN valence electrons and are the most reactive nonmetals; includes gases ($Cl$, $F$), a liquid ($Br$), and a solid ($I$) at $25^{\circ}C$.

Noble Gases

Group 18 (VIII) elements that have a full valence shell (EIGHT valence electrons), making them very stable and inert (non-reactive).

Rare Earth Metals

A set of seventeen chemical elements specifically consisting of the fifteen lanthanoids plus scandium ($Sc$) and yttrium ($Y$).

Metals

Elements found on the lower left-hand side of the table (below the staircase) that are typically shiny, malleable, ductile, and great electrical conductors.

Non-metals

Elements found on the upper right-hand side of the table (above the staircase, plus Hydrogen) that are poor electrical conductors and are dull and brittle.

Metalloids (Semimetals)

Elements found on both sides of the zigzag line (like silicon, arsenic, and boron) that possess both metallic and nonmetallic properties.

Atomic Size Trend

A property that increases from top to bottom of a family due to added electron shells and decreases from left to right due to greater nuclear attraction.

Shielding Effect

The process where outer electrons are shielded from the nucleus by inner electrons.

Ionization Energy

The minimum amount of energy required to remove an electron from an atom; it increases from left to right and decreases down a group.

Metallic Trends

Pattern where metallic properties decrease from left to right across a period and increase from top to bottom down a group.

Valence Electrons

The electrons of an atom that can participate in the formation of chemical bonds, determined by the periodic table group number.