Mendeleev

The one who organized the elements by increasing the atomic mass and make the same elements in the same row have similar properties.

Mendeleev

The one who organized the elements by increasing the atomic mass and make the same elements in the same row that have similar properties.

Moseley

The one who rearranged the elements by increasing atomic number.

Periodic law

“when elements are arranged in order of increasing atomic number, there’s a periodic pattern in their physical and chemicals properties.”

Period

the horizontal rows of the periodic table.

Group

The vertical rows of the periodic table.

S block

Representative elements

P block

Representative elements

D block

Transition metals

F block

Inner transition metals

Alkali metals

Highly reactive chemical elements in group 1 of the periodic table

Li, Na, K, Rb, Cs, Fr

Alkaline earth metals

Highly reactive and shiny chemical elements located in group 2

Be, Mg, Ca, Sr, Ba, Ra

Transition metals

Large blocks of metallic element are in group 3 through 12.

Halogens

Highly reactive nonmetallic elements in Group 17

Noble gases

Stable, odorless, colorless, nonmetallic gases in group 18.

Metal

Lustrous, malleable, and good conductors of heat and electricity located on the left of the staircase.

Non metal

Non-lustrous, brittle, and poor conductors located on the right side of the staircase (include H).

Metalloids

Touch the staircase and have properties of both metals and non metals.

Electron configuration

How electrons are distributed.

Principal energy levels

Describes the average distance of an electron from the nucleus.

Sublevels

Correspond to the different areas an electron can be located in an atoms.

Atomic orbitals

Each sublevel is oriented differently in 3D space, and each orbitals can hold only two electrons.

Aufbau Principle

Electrons enter sublevels with the lowest energy first.

Orbital nation

Uses circles to represent atomic orbitals with a label underneath to indicate sublevel and energy level.

Pauli Principle

Atomic orbitals can only hold two electrons at most and they must have opposite spins.

Hund’s Rule

in a sublevel with more than one orbital, put one electron into each orbitals before putting 2 electrons into any one orbital.

Isoelectronic

Two atoms have the same number of electrons.

Valence Electrons 

Electrons located in the outermost energy level.

Atomic radius

½ of the distance between the nuclei of two like atoms.

Nuclear charge

Magnitude of attraction from nucleus.

Shielding effect

The inner electrons “shield” or block the attraction from the nucleus.

Ionization energy

The amount of energy required to remove an electron from a gaseous atom.

Ionic size

The size of an atom changes according to its charge: it’s larger if the charge is negative and smaller if it’s positive.

Electronegativity

Tendency for an element to attract electrons when chemically combined with another element.