bonding and periodic properties Flashcards
who came up with how elements should be grouped?
dmitri mendeleev and lothar meyer
who is mostly credited for organization of the table? why?
mendeleev because he used chemical properties to organize the table and predicted some missing elements
what was mendeleev’s table based on
atomic masses
about 35 years later who discover the nuclear atom?
ernest rutherford
who developed the concept of the atomic number?
henry moseley
what is periodicity?
the repetitive pattern of a property for elements based on atomic number
Zeff =Z -S
Zeff is effective nuclear charge where Z is the atomic number and S is a screening constant
effective nuclear charge
increases across a period and decreases down a group
add e- across, add energy level down
what is half of the shortest distance separating two nuclei during collision or atoms
nonbonding atomic radius
van fee Waals radius
atomic radius
decreases across period
increases down group
cations
smaller than parents, outer most e- removed and repulsion between e- is reduced
anion
larger than parent, electron added and repulsion between e- is increased
ions have the same number of e-, same electron configuration
isoelectronic series
what is ionization energy?
the minimum energy required to remove an electron from the ground state of a gaseous atom or ion
the higher the ionization energy
the harder it is to remove an e-
ionization energy
increases across
decreases down
what is electron affinity?
the energy change accompanying the addition of an e- to a gaseous mixture
electron affinity
increases across period
exceptions include 2A, 5A, 8A but it is full-half full
no change in a group
electronegativity
increases across
decreases down
what is electronegativity?
the ability of an atom in a molecule to attract e- to itself
what do metals tend to form
cations
what color is the flame of Li? Na? K?
Li pink/red
Na orange
K purple
ionic bonding
e- are transferred
covalent bonding
e- are shared
