Unit 3 Test Review: History and Structure of the Atom, Isotopes, Ions, Bohr Models, Periodic Table, & Nuclear Chemistry

Flashcards covering the history of the atom, atomic structure, isotopes, ions, Bohr models, the periodic table, and basic nuclear chemistry concepts.

John Dalton

Scientist who developed the first modern atomic theory.

Dalton's Atomic Theory (Part 1)

All matter is made of atoms, which are indivisible and indestructible.

Dalton's Atomic Theory (Part 2)

All atoms of a given element are identical in mass and properties.

Dalton's Atomic Theory (Part 3)

Compounds are formed by a combination of two or more different kinds of atoms.

Dalton's Atomic Theory (Part 4)

A chemical reaction is a rearrangement of atoms.

Cathode Ray Tube

The instrument used by J.J. Thomson in his experiments to discover electrons.

J.J. Thomson's Discovery

Discovered the electron, a negatively charged particle.

Electron Charge

Negative.

Ernest Rutherford's Discovery

Discovered the atomic nucleus.

Gold Foil Experiment

The experiment Rutherford used to discover the nucleus.

Nucleus Charge

Neutral

Niels Bohr's Atomic Model

Described electrons as being arranged in specific energy levels or orbits around the nucleus.

Proton

Subatomic particle located in the nucleus with a positive charge.

Neutron

Subatomic particle located in the nucleus with no charge (neutral).

Electron

Subatomic particle located in the electron cloud/orbitals with a negative charge.

Atomic Number

The number of protons in an atom, which determines the element.

Mass Number

The total number of protons and neutrons in an atom's nucleus.

Isotope

Atoms of the same element that have the same number of protons but different numbers of neutrons (and thus different mass numbers).

Isotope Notation (e.g., Carbon-12)

The number after the dash signifies the mass number of the isotope.

Average Atomic Mass

The weighted average of the atomic masses of all naturally occurring isotopes of an element, based on their relative abundances.

Ion

An atom or molecule that has gained or lost one or more electrons, resulting in a net electrical charge.

Cation

A positively charged ion, formed when an atom loses electrons.

Anion

A negatively charged ion, formed when an atom gains electrons.

Valence Electrons

Electrons in the outermost shell of an atom, involved in chemical bonding.

Groups (Periodic Table)

Vertical columns on the periodic table; elements in the same group tend to have similar chemical properties.

Periods (Periodic Table)

Horizontal rows on the periodic table; elements in the same period have the same number of electron shells.

Metals

Elements typically found on the left and center of the periodic table, characterized by properties like good conductivity, malleability, and ductility.

Nonmetals

Elements typically found on the upper right side of the periodic table, characterized by properties like poor conductivity and brittleness.

Metalloids

Elements with properties intermediate between metals and nonmetals (e.g., Boron, Silicon, Germanium).

Alkali Metals

Common name for elements in Group 1 of the periodic table.

Alkaline Earth Metals

Common name for elements in Group 2 of the periodic table.

Transition Metals

Common name for elements in Groups 3-12 of the periodic table.

Chalcogens (or Oxygen Group)

Common name for elements in Group 16 of the periodic table.

Halogens

Common name for elements in Group 17 of the periodic table, known for being highly reactive nonmetals.

Noble Gases

Common name for elements in Group 18 of the periodic table; considered 'inert' due to a full outermost electron shell, making them very unreactive.

Semiconductor

A material with electrical conductivity between that of a conductor and an insulator, often a metalloid.

Nuclear Fusion

A nuclear reaction where two or more atomic nuclei collide at high speed and join to form a new, heavier nucleus.

Nuclear Fission

A nuclear reaction where a heavy nucleus splits into two or more smaller nuclei, releasing energy.

Alpha Radiation

A type of radiation with the weakest penetrating power, consisting of alpha particles (helium nuclei, ⁴₂He or α).

Beta Radiation

A type of radiation of intermediate penetrating power, consisting of beta particles (electrons, ⁰₋₁e or β).

Gamma Radiation

A type of electromagnetic radiation with the strongest penetrating power, consisting of high-energy photons (⁰₀γ or γ).

Effect of Alpha Decay

The atomic number decreases by 2, and the mass number decreases by 4.

Effect of Beta Decay

The atomic number increases by 1, and the mass number remains the same.

Effect of Gamma Emission

There is no change in the atomic number or the mass number of the nucleus.