Periodic Table

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Periodic Table

chart of elements arranged to rows/ columns according to physical and chemical properties

Johann Dobereiner

law of triads (grouped into 3 according to atomic mass) weight of middle element = 1st and 3rd element / 2

John Newlands

law of octaves. every eighth element has similar properties in increasing order (atomic mass)

Dmiti Mendeleev

“father of the periodic table” aloted space for new elements

Julius Lothar Meyer

arranged according to physical properties

Henry Moseley

arranged in atomic number instead

column

per row

groups

per column

1st - 2nd column

s

3rd - 10th

d

11th - 16th

p

period #

electronic shells

Periodic Trends

specific patterns in the properties of chemical elements that are revealed in the periodic table of elements

shielding effect

electrons attracted to nucleus ; electrons shield other electrons which are father from the nucleus

nuclear charge

measure of the ability of protons in the nucleus to attract the electrons

atomic radius

distance from the nucleus to outermost cloud of e ; determines the size of the element ; going down = increases going left - right = decreases

ionic radius

radius of an atom’s ion found in a crystal lattice ; positive ions become smaller that their neutral atoms ; negative ions >> neutral atoms

electronegativity

atoms attracts a shared pair of e- toward itself ; high electronegativity = greater attraction for bonds electrons

ionization energy

amount of energy needed to remove an electron from a neutral atom in its gaseous state ; closer and more tightly bound an electron is to the nucleus, more difficult it will be to remove

electron affinity

ability of an tom to accept an electron ; elements with almost complete electrons in the subshells have low affinity values but are relatively stable

reactivity

tendency of an tom to react with other elements ; higher reactivity means being more prone to chemical destruction in corrosion

metals

loose e when they react so, (___) reactivity is based on Ionization energy (bottom / left corner) ; low ionization energy = high reactivity

non metals

gain e when they react so, (_______) reactivity is based on high electronegativity ; high electronegativity = high reactivity