Atoms, Ions, and the Periodic Table

These flashcards cover key concepts and vocabulary related to atoms, ions, and the periodic table as discussed in Chapter 2 of the lecture notes.

Atom

The smallest unit of an element, consisting of protons, neutrons, and electrons.

Ion

An atom or molecule that has a net electrical charge due to the loss or gain of one or more electrons.

Cation

A positively charged ion that has lost one or more electrons.

Anion

A negatively charged ion that has gained one or more electrons.

Atomic Number

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

Mass Number

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

Isotope

Atoms of the same element that contain the same number of protons but different numbers of neutrons.

Dalton's Atomic Theory

The theory that all matter is composed of atoms, which are indivisible particles.

Subatomic Particles

The particles that make up an atom, including protons, neutrons, and electrons.

Periodic Table

A tabular arrangement of the chemical elements organized by increasing atomic number.

Law of Conservation of Mass

Mass is not created or destroyed in a chemical reaction.

Law of Definite Proportions

A chemical compound always contains exactly the same proportion of elements by mass.

Electrons

Negatively charged subatomic particles found in the electron cloud of an atom.

Protons

Positively charged subatomic particles located in the nucleus of an atom.

Neutrons

Uncharged subatomic particles found in the nucleus of an atom.

Nucleus

The central core of an atom, containing protons and neutrons.

Atomic Mass Unit (amu)

A unit of mass used to express atomic and molecular weights, based on the mass of carbon-12.

Scanning Tunneling Microscope (STM)

An advanced microscope that can image individual atoms on surfaces.

Dmitri Mendeleev

A chemist who created one of the first versions of the periodic table.