Elements and the Periodic Table

Alkali metal

Elements in Group 1 of the periodic table, like lithium, sodium, and potassium, are alkali metals. Alkali metals are highly reactive elements that have one electron in their outer shell.

Conductivity

The ability of a material to let heat or electricity pass through. Conductivity. Conductivity is how well a material allows heat or electricity to flow through it.

Diatomic molecule

A particle consisting of two atoms. Diatomic molecule. A diatomic molecule is a molecule made up of two atoms bonded together, like oxygen O2 or hydrogen H2.

Group

Elements in the same vertical column of the periodic table. Group. In Science, a group is a column of elements in the periodic table that have similar chemical properties.

Halogen

An element in Group 17 of the periodic table, like chlorine. Halogen. Halogens are reactive nonmetals that can form salts when combined with metals.

Luster

The way a mineral's surface reflects light. Luster. Luster is the appearance or shine of a mineral's surface when it reflects light.

Metal

An element that is a good conductor of heat and electricity. Metal. Metals are materials that allow heat and electricity to pass through them easily because of their free-moving electrons.

Metalloid

An element that shares properties with metals and nonmetals, like a semiconductor. Metalloid. A metalloid is an element that has characteristics of both metals and nonmetals and can conduct electricity under certain conditions.

Noble gas

An element in Group 18 of the periodic table, like helium, neon and argon. Noble gas. A noble gas is a chemical element with a full outer shell of electrons, making it very stable and unreactive.

Nonmetal

An element that is a poor conductor of heat and electricity. Nonmetal. In simple terms, a nonmetal is an element that lacks the ability to conduct heat or electricity well.

Period

A horizontal row of elements of the periodic table. period. In Science, a period is a row in the periodic table where elements have the same number of electron shells.

Periodic table

A chart of all the elements, arranged by their physical and chemical properties. Periodic table. The periodic table is a visual representation of the chemical elements organized by increasing atomic number, showing patterns in their properties.

Radioactive decay

The breakdown of an unstable atomic nucleus, this releases particles and energy. Radioactive decay. Radioactive decay is the process where an unstable atom releases energy and particles to become more stable.

Radioactivity

The ability of an unstable nucleus to emit radiation. Radioactivity. It is the process where unstable atoms release energy in the form of particles or rays to become stable.

Semiconductor

A material that conducts electricity under certain conditions, it has properties of both metals and nonmetals. Semiconductor. A semiconductor is a substance that can control electrical currents, making it crucial for electronic devices like computers and smartphones.

Transition element

An element in Group 3 to Group 12 of the periodic table, they are all metals. Transition element. Transition elements are metals with unique properties like forming colorful compounds due to their ability to use different electron shells for bonding.