Chemistry Intensified - Periodic Trends/Nuclear Reactions/Half Life

What is the equation for half life?

TOTAL time sample was around

half life

starting amount

final amount

alkali metals

alkaline earth metals

lanthanide

actinide

metalloids

halogens

noble gases

What is coloumbs law?

the greater the distance, the less attraction there is

the less distance, the more attraction there is

What are valence electrons?

electrons in HIGHEST energy level

What are core electrons?

all electrons EXCEPT valence electrons

What is the effective nuclear charge?

STRENGTHENING of the nucleus across a period

What is atomic radius/TREND

distance measured from nucleus to outer electron trend

DECREASES as you go across the period

INCREASE as you go down the group

What is ionization energy/TREND

energy required to remove the last electron from an atom

INCREASE as you go across the period

DECREASE as you down the group

What is a cation?

an ion with a POSITIVE charge

What is an anion?

an ion with a NEGATIVE charge

What is ionic radius/TREND?

distance from nucleus of an ION to electron cloud

DECREASE as you across the period

INCREASE as you go down the group

Who is Johann Dobreiner

classified elements into TRIADS based on mass averages

Who is John Newlands

arranged elements into OCTAVES by increasing atomic mass

Who is Dimitri Mendeleev?

predicted properties of unknown elements, designed a table that had arrangement of elements based on atomic mass

Who is Henry Moseley?

developed moseleys law, showed relationship between atomic wavelength and number

How to determine if attraction force is stronger/weaker

as you go across a period, the attractive force increases

as you go down a group, it decreases

How to determine if valence electrons are closer/farther from nucleus

as you go down the group, ve distance increases

as you go across the period, ve distance decrease

shielding effect

effective nuclear charge

octave rule?