Electron Configuration & the Periodic Table

group or family

A column on the periodic table.

period or series

A horizontal row of elements in the modern periodic table

Elements with similar properties and electron configuration

A located in the same group.

hydrogen

A unique element that cannot be reasonably included in any single group of the periodic table. This is the most abundant element in the universe.

radioactive

All of the actinides are _?_.

valence electrons

Electrons on the outermost energy level of an atom.

alkali metals

Elements in the first group which include lithium, sodium, potassium, rubidium, cesium, and francium. These are extremely reactive metals.

lanthanides

The 14 elements from cerium (atomic number 58) to lutetium (atomic number 71).

actinides

The 14 elements from thorium (atomic number 90) to lawrencium (atomic number 103) are called _?_.

octet

The eight electrons in outer energy level.

helium

The element which has a configuration similar to the alkaline earth metals, but it is included in the noble gas group because it is a nonreactive gas.

alkaline earth metals

The elements in Group 2 (beryllium, magnesium, calcium, strontium, barium, and radium) are called the _?_ . These elements have two valence electrons, both of which reside in the outermost s sublevel. The general electron configuration of all _?_ is ns2.

halogens

The elements in group 17 are know as _?_. They are very reactive nonmetals.

noble gases

The elements in group 18 are know as _?_. They are very nonreactive gases.

transition element

The elements that are found in Groups 3-12 (which is the d sublevel block) on the periodic table.

Francium (Fr)

The most reactive metal.

Fluorine

The most reactive nonmetal.

one

The number of electrons that alkali metals have in their outermost energy level.

two

The number of electrons that alkaline earth metals have in their outermost energy level.

representative (main-group) elements

The s block and p block elements together are called the _?_.