refers tothe repeated pattern of similar chemical properties as elements are arranged in order of increasing atomic number. Elements with similar chemical properties are placed in the same group on the periodic table.

atomic number

the periodic table is ordered by the ______ _______.


these contain elements with similar outer-shell electronic configurations. For instance, atoms of the alkali metals in the first group have a half-filled s-orbital (s1) in their outer shell.


these are numbered 1-7 and each contain elements with electrons in the same outer shell. The number of the period is the same as the number of the outer shell.


contains elements in group 1 (alkali metals) and group 2 (alkaline earth metals).


contains elements in groups 13-18.

main group elements

elements in the s- and p-blocks are often referred to as this.


contains transition metals, and is located between the s- and p-blocks. It contains elements in which the five orbitals (with a maximum of 10 electrons) of the d-shell are progressively being filled.


contains the lanthanides and actinides. The seven orbitals are able to contain a maximum of 14 electrons.


any element of the lanthanide series with atomic numbers 57 through 71


any of a series of radioactive elements with atomic numbers 89 through 103


the tendency of an atom or radical to attract electrons in the formation of an ionic bond

ionisation energy

The minimum amount of energy that is required to remove an electron from an atom or ion, in the gaseous state

core charge

same as the number of valence electrons

valence electrons

electrons in the outer shell


elements on the right side of the periodic table. , elements that are usually dull in appearance, poor conductors of heat and electricity, gases at room temperature


left of the zigzag line, shiny, malleable, ductile, good conductors of electric current, good conductors of thermal energy


some elements, such as germanium, silicon, arsenic and tellerium are located across periods and display both mettallic and non-metallic properties. These are called...

nobel gases

the elements of group 18, including helium, neon, argon, krypton and xenon. They are unreactive, due to the outer-shell electron configuration of s2p6, a stable arrangement.


Compounds are formed when two atoms of two or more elements chemically combine in fixed proportions. Each compounds has its own properties, which are quite different from those of the elements it contains.

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