Chem Q2 Periodic table trends

John Newlands

Arranged known elements by their properties and increasing atomic mass

Dmitri Mendeleev

Arranged the elements by increasing atomic mass. Started a new row every time he noticed repeating properties

Henry Moseley

The atomic number is the basis for the periodic table

A vertical column is called a

Group

Valence electrons

Electrons in the outermost energy level of an atom

Periodic Law

When elements are arranged according to their atomic numbers, elements with similar properties appear at regular intervals.

Atomic Radius

The measurement of atomic size, determined by calculating the distance between the center of the nucleus to the most outer electron

Electronegativity

Indicates an atom’s ability to attract electrons

Ionization

The amount of energy required to remove and electron from a neutral atom

Electron shielding

When inner electrons shield the outermost electrons from the positive charge of the nucleus reducing the attraction between the nucleus and outermost electrons.

Nuclear Charge

The positive charge of an atom’s nucleus, which increases as the # of protons increase

Electronegativity and Ionization energy increases

Atomic radius decreases

Right