Chapter 4: Atoms and Elements

These flashcards cover key vocabulary and concepts related to atoms, elements, and the periodic table as discussed in Chapter 4.

Element

A pure substance made of only one type of atom.

Atomic Number

The number of protons in an atom's nucleus, which determines the element's identity.

Mass Number

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

Isotope

Atoms of the same element that have the same atomic number but different numbers of neutrons.

Chemical Symbol

A one or two-letter abbreviation for an element.

Periodic Table

A tabular arrangement of elements based on increasing atomic number.

Proton

A positively charged subatomic particle found in the nucleus of an atom.

Neutron

A neutral subatomic particle found in the nucleus of an atom.

Electron

A negatively charged subatomic particle that orbits the nucleus of an atom.

Metalloid

An element that exhibits properties of both metals and nonmetals, located along the zigzag line of the periodic table.

Noble Gas

An unreactive element in Group 8A (18) of the periodic table, with a full outer shell of electrons.

Alkali Metal

A highly reactive element in Group 1A (1) of the periodic table.

Alkaline Earth Metal

An element in Group 2A (2) of the periodic table.

Halogen

An element in Group 7A (17) of the periodic table, known for being highly reactive.

Ductile

A property of metals that allows them to be stretched into thin wires.

Malleable

A property of metals that allows them to be hammered into thin sheets.

Atomic Mass Unit (amu)

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