Scientist credited with classifying the elements in order

Structure made up of two or more atoms, for example two hydrogen atoms and one oxygen atom = one of these

The largest group of elements on the PT, have the physical properties of being malleable and shiny

Matter cannot be created nor destroyed only transformed into another type of energy

A property of a substance that can be observed without changing the chemical identity of the substance - for example: color, shape, hardness, texture...

Scientist who filled in the missing elements on the Periodic Table

Part of an atom that is neither negatively nor positively charged

A physical property of metals which means it can be flattened into a thin sheet

Energy from the chemical reaction is absorbed and surrounding temperature decreases

A property that describes how a substance chemically changes into a new or different substance - for example: flammability

The name for each of the 7 rows on the PT

The smallest building block of matter

A physical property of metals which means it is shiny or dull

Law that states when elements are placed on the PT in order of atomic number, their physical and chemical properties go in order too. It helped Mendeleev make element predictions back in mid 1800s.

Inert or non-reactive elements grouped into family #18 on the PT - for example: Krypton, Neon, Helium

Name for the 18 columns on the PT which share similar properties

The part of the atom found in an element's Atomic Number

A physical property of non-metals meaning breakable

The process by which one substance is changed into another substance

Elements that react violently with water such as Magnesium, Sodium and Potassium. They are in the first two groups #1 and #2 Alkali Metals and Alkali Earth Metals on the PT.

A classification system used to order all of the elements, known as the alphabet of the universe

Negatively charged part of the atom that reacts with other atoms

The element group on the PT that includes gases and liquids

Energy from the chemical reaction is released and surrounding temperature increases

Elements that have some properties of Metals and Non-Metals. They are used in many electronics.