The number of protons in an atom's nucleus; it determines the element's position in the table.
Vertical columns that group elements with similar chemical properties.
Elements in Group 17, such as Fluorine (F), that are very reactive nonmetals.
Horizontal rows that indicate the number of electron shells.
Provides a systematic way to understand the relationships between various elements.
The weighted average mass of an element's isotopes, usually found below the element symbol.
Elements in Group 1, such as Lithium (Li), that are highly reactive and soft.
Elements in Group 2, such as Beryllium (Be), that are reactive and harder than alkali metals.
Elements in Group 18, such as Neon (Ne), that are inert gases and non-reactive.
A tabular arrangement of chemical elements, organized by increasing atomic number.
Elements that exhibit properties of both metals and nonmetals (e.g., Silicon, Arsenic).
It helps predict the chemical behavior of elements based on their position.
Good conductors of heat and electricity, malleable, and ductile (e.g., Iron, Copper).
Poor conductors, brittle in solid form (e.g., Carbon, Nitrogen).
It aids in predicting the outcomes of chemical reactions.
Generally increases down a group and decreases across a period.
The energy required to remove an electron; it increases across a period and decreases down a group.
A measure of an atom's ability to attract electrons; it increases across a period and decreases down a group.
