Periodic table

Periodic Table

A chart of the elements arranged into rows and columns according to their physical and chemical properties.

Law of Triads

States that the atomic weight of the middle element in a triad was approximately the average of the atomic weight of the first and third elements.

Law of Octaves

When elements are arranged in increasing atomic mass, the properties of elements repeat for every 8 elements.

Dimitri Mendeleev

Elements are arranged according to increasing atomic mass, with elements in the same column having similar properties.

Groups/Families

Vertical columns of elements that have similar characteristics.

Periods

Horizontal rows in the periodic table.

s-block elements

Valence electrons are in the s-blocks, classified as Representative elements/group A.

p-block elements

Valence electrons are in the p-blocks, classified as Representative elements/group A.

d-block elements

The elements' electrons are filling up the d-orbital, classified as transition metals.

f-block elements

Fills up the f-orbital, classified as inner transitional metals. 4f- Lanthanide Series, 5f- Actinide Series.

Representative Elements (Group A)

Elements with valence electrons in the s/p-orbital, can donate/gain electrons during a chemical reaction to attain octet.

Transition Metals (Group B)

Elements with valence electrons in the d-orbital, group number depends on the number of electrons in the d-orbital, period number = +1, valence electrons = +2.

Inner Transition Metals

Elements with the last electron in the f-orbital, group number depends on the sublevel, period number = +2.

Periodic Trends

Specific patterns in the properties of chemical elements that are revealed in the periodic table.

Shielding Effect

Electrons are attracted by the nucleus but repelled by other electrons, thus "shielding" other electrons from the nucleus of the atom.

Nuclear Charge

Measure of the ability of protons in the nucleus to attract the negative electrons in orbit around the nucleus.

Atomic Radius

Distance from the nucleus to the outermost cloud of electrons, determines the size of the element.

Ionic Radius

Radius of an atom's ion found in a crystal lattice, positive ions become smaller than their neutral ions while negative ions are larger than neutral ions.

Electronegativity

The tendency of an atom to attract a shared pair of electrons toward itself.

Electron Affinity

The ability of an atom to accept an electron.

Reactivity

Tendency of an atom to react with other elements.

Metallic Character

Metallic luster, high density, high thermal conductivity, and high electrical conductivity.