GE-Chem Lab: Quiz 1 (Lesson 1)

Matter

Anything that occupies space and has mass.

Atoms

The basic building blocks that compose matter.

Atoms

The smallest identifiable unit of an element.

Leucippus and Democritus

Theorized that matter is composed of small, indivisible particles.

Democritus

Coined the term “atomos.”

Antoine Lavoisier

Established the “Law of Conservation of Mass.”

Law of Conservation of Mass

Matter cannot be created or destroyed, only rearranged in a chemical reaction.

Joseph Proust

Proposed the “Law of Definite Proportions.”

Law of Definite Proportions

Different samples of the same element contain its constituent elements in the same proportion by mass.

John Dalton

Formalized the Atomic Theory.

Wilhelm Rontgen

Discovered X-rays while studying vacuum tubes and cathode rays.

Henri Becquerel

Discovered spontaneous emission of radiation from Uranium ores.

Marie Curie

Coined the term “radioactivity” for observed spontaneous radiation.

Joseph John Thomson

Discovered electrons as the first subatomic particle.

Ernest Rutherford

Demonstrated at least two distinct types of radiation.

Alpha and beta radiation

Two distinct types of radiation.

Hans Geiger

Proved that α particles are He 2+ ions with Rutherford.

1927 Solvay Conference

Marked the birth of Quantum Mechanics.

Max Planck

Proposed quantization of energy of light to explain Blackbody radiation.

Albert Einstein

Provided theoretical background for the Photoelectric Effect.

Photoelectric Effect

Electrons are emitted from a plate when exposed to light.

Robert Millikan

Precisely determined the magnitude of the electron’s charge.

Ernest Rutherford, Hans Geiger, and Ernest Marsden

Discovered protons by bombarding gold foils with α particles.

James Chadwick

Discovered neutrons.

Protons

Positively charged particles in an atom.

Electrons

Negatively charged particles in an atom.

Neutrons

Particles with no charge in an atom.

Unified atomic mass

Defined as 1/12 of the mass of a carbon atom with 6 protons and 6 neutrons.

Nucleus

The dense core of the atom containing protons and neutrons.

Electron cloud

The region where electrons are located, comprising most of the atom’s volume.

Element

A pure substance that cannot be broken down by chemical reactions.

Atomic number

Indicates the number of protons in an element.

Z

Symbol for atomic number.

Julius Lothar Meyer

Created a Periodic Table of Elements similar to Mendeleev’s work.

Clemens Winkler

Discovered eka-silicon, now known as Germanium.

Alkali metals

Soft, shiny metals with low melting points.

Alkaline earth metals

Good conductors of heat and electricity, react with water to form basic solutions.

Halogens

Very reactive elements that exist as diatomic molecules.

Noble gases

Stable elements that rarely combine with others.

Isotopes

Atoms with the same number of protons but different numbers of neutrons.

Werner Heisenberg

Formulated the Quantum Theory.

Schrodinger equation

A wave equation describing the electronic structure of atoms.

Quantum Numbers

Numerical labels for the probable location of electrons in an atom.

s-orbital

Has a spherical shape.

p-orbital

Has a dumbbell shape.

Electron configuration

Arrangement of electrons in an atom’s orbitals.

Ground state

The lowest energy arrangement of electrons.

Aufbau Principle

As protons are added one by one to the nucleus to build up the elements, electrons are similarly added to the atomic orbitals.

Pauli Exclusion Principle

No two electrons can have the same set of four quantum numbers.

Hund's Rule

The most stable arrangement of electrons has the greatest number of parallel spins.

Valence electrons

Electrons in the outermost shell of an atom.

Valence shell

The outermost shell of an atom.

Periodic trends

Patterns in the periodic table illustrating different aspects of elements.

Atomic radius

Half the distance between the nuclei of two adjacent atoms.

Ionic radius

The radius of a cation or anion.

Ionization energy

Energy required to remove the most loosely held electron from an atom.

Electron affinity

Energy change when an electron is accepted by an atom.