Chp 6 - Honors Chem

Mendeleev

Formulated the periodic law and arranged elements by increasing atomic mass, predicting the properties of undiscovered elements.

Moseley

Established the atomic number based on protons and arranged the periodic table by atomic number.

Periodicity

Recurring patterns in element properties as you move across periods and groups in the periodic table.

Electrostatic Force

The force of attraction between positively charged protons and negatively charged electrons, influenced by distance and shielding.

Periodic Law

Elements ordered by increasing atomic number show repeating patterns in their physical and chemical properties.

Valence Electrons

Electrons in the outermost energy level of an atom, crucial for bonding and reactivity.

Core/Kernel Electrons

Electrons in energy levels that are not the outermost level, contributing to the shielding effect.

Alkaline Earth Metals

Group 2 elements that are reactive, have low densities, melting points, and form basic solutions (pH > 7).

Transition Metals

Elements with valence electrons in two different shells, often forming colored compounds and used as catalysts.

Alkali Metals

Group 1 elements, highly reactive and electropositive, known for forming 1+ cations.

Metals

Elements that are ductile, malleable, lustrous, and good conductors of heat and electricity.

Nonmetals

Elements that are brittle, poor conductors, and often have high electronegativities.

Metalloids

Elements with properties intermediate between metals and nonmetals, useful as semiconductors.

Halogens

Group 17 elements that are highly reactive, electronegative, and typically toxic.

Noble Gases

Group 18 elements with full valence electron shells, chemically inert and nonreactive.

Atomic Radius Trends

Increases down a group and decreases across a period due to changes in nuclear charge and shielding.

Ionic Radius Trends

Increases down a group and decreases across a period, similar to atomic radius trends.

Electronegativity

A measure of an atom’s ability to attract electrons in a bond, increasing across periods and decreasing down groups.

Ionization Energy

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

Cations

Positively charged ions formed by the loss of electrons.

Anions

Negatively charged ions formed by the gain of electrons.

Nuclear Charge

The total charge in the nucleus due to protons, influencing the force of attraction on electrons.

Shielding Effect

Core electrons reduce the attractive force between the nucleus and valence electrons.

First Ionization Energy

The energy required to remove the first electron from an atom, forming a cation.

Second Ionization Energy

The energy required to remove a second electron, creating a new cation.

Covalent Bonds

A type of bond where electrons are shared between atoms; can be polar (uneven sharing) or nonpolar (even sharing).

Ionic Bonds

Bonds formed by the transfer of electrons between atoms, typically between metals and nonmetals.

Polar Bonds

Bonds with unequal sharing of electrons, leading to partial charges.

Nonpolar Bonds

Bonds with equal sharing of electrons, resulting in no charge separation.

Malleable

The ability of a material (usually metals) to be hammered into thin sheets without breaking.

Coulombic Forces

The force of attraction between positive and negative charges in an atom, affecting many atomic properties.