Atoms and the Periodic Table Flashcards

Flashcards covering atomic structure, subatomic particles, isotopes, ions, and the organization and families of the periodic table based on the lecture notes.

Atom

The smallest piece of an element that retains the properties of that element, made up of smaller subatomic particles.

Nucleus

The central part of an atom containing protons and neutrons; it makes up most of the mass of an atom but almost none of the size.

Electron Cloud

The region making up most of the volume of an atom where electrons move so fast they are described as being everywhere at once; contains different energy levels.

Protons

Positively charged ($+$) subatomic particles located within the nucleus.

Neutrons

Subatomic particles located within the nucleus with no charge ($0$).

Electrons

Negatively charged ($-$) subatomic particles found in the electron cloud at different distances from the nucleus.

Energy Levels

Concentric spheres in the electron cloud where electrons orbit; the first level holds 2 electrons, the second holds 8, and the third holds up to 18.

Atomic Number

The number of protons in an atom, which identifies the element and the number of electrons in a neutral atom.

Atomic Mass

The weighted average mass of an atom of a naturally occurring sample of an element, often not a whole number.

Mass Number

The total number of protons and neutrons in the nucleus of an atom; it is not listed directly on the periodic table.

Isotopes

Atoms of the same element that have the same number of protons but different numbers of neutrons, and therefore different mass numbers.

Hyphen Notation

A way to express isotopes by writing the element name followed by the mass number, such as Lithium-7.

Nuclear Symbol

A way to represent an isotope showing the element's symbol with the Mass Number ($A$) as a superscript and Atomic Number ($Z$) as a subscript.

amu

Atomic mass unit; the unit used to express the mass of isotopes.

Percent Abundance

How much of a particular isotope exists in a naturally occurring sample of an element.

Ions

Atoms or molecules that have a ($+$) or ($-$) charge due to having gained or lost electrons.

Anion Naming Rule

Negative ions (like chloride) are identified with an “-ide” ending.

Chemical Formula

An abbreviation for a chemical compound that uses element symbols and gives the ratios of the elements, such as $NH_3$.

Groups

Vertical columns on the periodic table organized by the number of electrons in the outer energy level (valence electrons).

Periods

Horizontal rows on the periodic table organized by the number of energy levels.

Alkali Metals

Elements belonging to Group 1 or Group IA.

Alkaline Earth Metals

Elements belonging to Group 2 or Group IIA.

Transition Metals

The large block of metallic elements located in the center of the periodic table, Groups 3 through 12.

Halogens

Nonmetal elements belonging to Group 17 or Group VIIA.

Noble Gases

Elements belonging to Group 18 or Group VIIIA.

Metalloids

Also known as semimetals, these elements have properties of both metals and nonmetals.