Periodic Table and Trends

A set of vocabulary flashcards covering key concepts related to the periodic table, periodic trends, and ionization.

Mendeleev

A Russian Chemist who developed the first periodic table in 1861, organizing elements by common properties and atomic weight.

Periodic Law

The physical and chemical properties of elements are periodic functions of their atomic numbers.

Groups

Vertical columns on the periodic table that group elements with similar properties.

Periods

Horizontal rows on the periodic table that indicate the number of energy levels in an atom.

Effective Nuclear Charge (Zeff)

The net positive charge experienced by valence electrons; calculated as Zeff = Z - S, where Z is the number of protons and S is the number of core electrons.

Valence Electrons

The outer shell electrons that are involved in chemical bonding.

Atomic Radius

The one-half distance between the nuclei of identical atoms in the solid state; generally increases down a group and decreases across a period.

Ionization Energy

The energy required to remove an electron from an atom; generally decreases down a group and increases across a period.

Electron Affinity

The energy change that occurs when an atom gains an electron; generally increases across a period.

Cations

Positively charged ions formed by losing electrons, resulting in a smaller ion size compared to the original atom.

Anions

Negatively charged ions formed by gaining electrons, resulting in a larger ion size compared to the original atom.

Alkali Metals

Elements in Group 1 of the periodic table, known for their high reactivity due to having one valence electron.

Alkaline Earth Metals

Elements in Group 2 of the periodic table, characterized by having two valence electrons and moderate reactivity.

Halogens

Elements in Group 17, known for existing in all states of matter and being highly reactive.

Noble Gases

Elements in Group 18, known for being inert and having complete valence electron shells.

Metalloids

Elements with properties intermediate between metals and nonmetals, located along the staircase line in the periodic table.