Periodic Properties of Elements

This set of flashcards covers key vocabulary and concepts related to the periodic properties of elements as discussed in the lecture notes.

Periodic Table of the Elements

A table that organizes elements by increasing atomic number and groups them by similar properties.

Electron Shells

Layers of electrons surrounding the nucleus of an atom; the number of shell increases across a period.

Valence Electrons

The outermost electrons of an atom, which determine chemical properties; increases by one across a period.

Electronegativity

A measure of an atom's ability to attract and hold onto electrons; tends to decrease down a group.

Ionization Energy

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

Electron Affinity

The energy change when an electron is added to a neutral atom; typically exothermic.

Metallic Character

A measure of how easily an atom can lose electrons; generally decreases across a period.

Non-metallic Character

A measure of how easily an atom gains electrons; generally increases across a period.

Mendeleev

A chemist credited with creating the periodic table; organized it based on the properties of elements.

Atomic Number

The number of protons in the nucleus of an atom; determines the element's identity.

Periodicity

The repeating pattern of chemical and physical properties of elements across periods of the periodic table.

Effective Nuclear Charge

The net positive charge experienced by valence electrons; calculated as Zeff = Z - S.

Bonding Atomic Radius

Half the distance between the nuclei of two bonded atoms; used to describe the size of an atom.

Non-bonding Atomic Radius

The van der Waals radius; half the shortest distance between the nuclei of two non-bonded atoms.

Ionic Size

The size of ions varies based on the number of electrons and the nuclear charge.

Cations

Positively charged ions formed when an atom loses one or more electrons.

Anions

Negatively charged ions formed when an atom gains one or more electrons.

Isoelectronic Series

A group of ions or atoms that have the same number of electrons; ionic radius decreases with increasing nuclear charge.

Ionization Energy (I)

The minimum energy needed to remove an electron from an atom or ion in its gaseous state.

First Ionization Energy (I1)

The energy required to remove the first electron from a gaseous atom.

Second Ionization Energy (I2)

The energy required to remove the second electron from a gaseous atom.

Trends in First Ionization Energy

Ionization energy generally increases across a period and up a group.

Factors Affecting Ionization Energy

Ionization energy is influenced by atomic size and effective nuclear charge.

Electron Configurations of Ions

Cations lose electrons from the highest energy levels; anions gain electrons to fill valence shells.

Electron Affinity

The change in energy when an electron is added to a neutral atom.

General Trend in Electron Affinity

Electron affinity typically increases across a period but has exceptions.

Group Trends

Elements within a group have similar properties which show periodic trends.

Alkali Metals

Soft metallic solids that react vigorously with water; found only in compounds in nature.

Alkaline Earth Metals

Metals that are harder and denser than alkali metals, reacting with water to form hydroxides.

Halogens

Highly reactive nonmetals that form negative ions; exist as diatomic molecules in nature.

Noble Gases

Inert gases with complete valence electron shells; high ionization energy and low reactivity.

Transition Metals

Elements found in groups 3 to 12; often have multiple oxidation states and form colored compounds.

Metalloids

Elements with properties intermediate between metals and nonmetals; often used as semiconductors.

Metal Properties

Typically shiny, malleable, ductile, good conductors of heat and electricity.

Nonmetal Properties

Typically dull, brittle, and poor conductors; can be solid, liquid, or gas at room temperature.

Metal-Oxide Compounds

Compounds formed from metals and oxygen, usually basic in nature.

Nonmetal-Oxide Compounds

Compounds formed from nonmetals and oxygen, typically acidic.

Comparison of Metals and Nonmetals

Metals are malleable and ductile with low ionization energies, while nonmetals are brittle and often form anions.

Flame Tests

Qualitative tests to identify alkali metals based on characteristic flame colors.

Reactivity Trends

Reactivity of elements often increases down a group for metals.

Chemical Reactivity of Metals

Metals tend to lose electrons to form cations when reacting with nonmetals.

Chemical Reactivity of Nonmetals

Nonmetals tend to gain electrons to form anions during chemical reactions.

Metalloid Characteristics

Metalloids possess both metallic and non-metallic properties, making them versatile.

Periodic Table Blocks

The periodic table is divided into s, p, d, and f blocks based on electron configurations.