Understanding the Periodic Table
The basic unit of a chemical element.
"An atom consists of a nucleus and one or more electrons."
A tabular display of the chemical elements, organized by atomic number, electron configuration, and recurring chemical properties.
"The periodic table is a useful tool for chemists."
The number of protons in the nucleus of an atom, which determines the chemical properties of an element and its place in the periodic table.
"Hydrogen has an atomic number of 1."
Elements that are poor conductors of heat and electricity.
"Chlorine is a nonmetal used in disinfection."
Elements with properties intermediate between metals and nonmetals.
"Silicon is a metalloid essential for electronics."
Elements found in group 1 of the periodic table, excluding hydrogen.
"Sodium is an alkali metal."
Elements found in group 2 of the periodic table.
"Calcium is an alkaline earth metal."
Elements found in groups 3-12 of the periodic table.
"Copper is a transition metal used in electrical wiring."
Elements found in group 17 of the periodic table.
"Fluorine is a halogen that is highly reactive."
Elements found in group 18 of the periodic table.
"Argon is a noble gas that is used in lighting."
A series of elements from lanthanum to lutetium in the periodic table.
"Neodymium, a lanthanide, is used in powerful magnets."
A series of elements from actinium to lawrencium in the periodic table.
"Uranium, an actinide, is used as a fuel in nuclear reactors."
Electrons in the outer shell of an atom that are involved in forming bonds.
"Carbon has four valence electrons available for bonding."
Atoms of the same element with different numbers of neutrons.
"Carbon-14 is an isotope used in radiocarbon dating."
The distribution of electrons of an atom or molecule in atomic or molecular orbitals.
"The electron configuration of oxygen is 1s² 2s² 2p⁴."