Periods

Definition

In the periodic table, periods refer to the horizontal rows. Each period corresponds to the number of electron shells an atom of an element in that period has.

Related terms

Atomic Radius:

This refers to the size of an atom. As you move across a period from left to right, atomic radius generally decreases due to increased nuclear charge pulling electrons closer.

Ionization Energy:

This is the energy required to remove an electron from a gaseous atom or ion. It generally increases across a period because increasing nuclear charge makes it harder for electrons to escape.

Electronegativity:

This measures how strongly atoms attract bonding electrons. It also generally increases across a period because atoms with more protons can attract electrons more strongly.