chapter 7 Flashcards
Pauli exclusion principle
no more than two electrons can be assigned to the same orbital. if there are two electrons in an orbital. they have opposite spins
the aufbau principle
electrons are assigned to shells and sub- shell in order of increasing energy
the two general rules used to predict the arrangements of electrons
- electrons are assigned to sub- shells in order of increasing n + l value
- for two subshells with the same N + l value, the electrons are first placed in the subshell with the lowest n value
effective nuclear charge
the net charge experienced by a charged electron in a multielectron atom due to the attraction force of the nucleus and the repulsive force of the other electrons
the trend with effective nuclear charge
it is greater for electrons closer to the nucleus,
ground state electron configuration
electrons are arranged in shells, sub shells and orbitals i order to produce the lowest energy for isolated atoms of an element
core electrons
electrons that are included in the noble gas configuration of an element ,are excluded when considering the chemistry of an atom.
valence electrons
electrons beyond the core electrons, these determine the chemical properties of an element
s block Elements
group 1A to 2A elements with their outermost electrons being on the s subshell
p block elements
group 3A to 8A elements with their outermost electrons being in the p orbital
hunds rule
the most stable arrangement of electron in a subshell is that with the maximum amount of unpaired electrons
electron configuration of anions
one or more electron is added to the valence shell of a non-metal atom so that it has an electron configuration of the next noble gas
electron configuration of cations
electrons are removed from the shell with the highest n. if there are multiple subshells within the nth shell, electrons are removed from the sub shell with the highest l value
paramagnetic
elements and compounds with unpaired electrons that are attracted to the magnetic field
diamagnetic
elements that have all their electrons paired and experience a sight re pulsion when exposed to a magnetic field
transition elements
elements that have their outermost electrons in the d(n-1) sub shell
lanthanides
elements that have their outermost electrons in the f(n-1) sub- shell
what does the period indicate in terms of quantum numbers
the period indicates the number of shells/ energy levels
what does the group number indicate in terms of electrons
the number of valence electrons
Give a reason why orbitals don’t have the same energy
as the number of electrons increases, the repulsion between the electros increases. the energy of the electron increases the further away it is from the nucleus of the atom
what do metals do when ionising
metals loose electrons when ionising and form cations, positive ions
what do non metals do when ionising
non metals gain electrons when ionising and form anions, negative ions
exceptions when it comes to ion configuration
Cr and Cu. the 3d sub- shells fill up first, making the atom more stable
what is the ionisation trend when it comes to transition metals
the p and s subshells of the outermost energy levels will loose electrons before the d subshell
atomic size
half the average distance between the centres of covalently bonded atoms
give the Zeff trend on the periodic table
- Zeff increases when moving from left to right across a period
- zeff decreases as you move down a group
give the atomic size trend
when moving across a period from left to right the atomic size decreases
when moving down a group the atomic size increases
isoelectronic
elements that have the same number of electrons
ionisation energy
the amount of energy required to remove an electron from an atom at gas phase
give the ionisation energy and enthalpy change trend in the periodic table and electron affinity
- when moving across a period from left to right the ionisation energy and the enthalpy change and electron affinity increases
- when moving down a group the ionisation energy and enthalpy change and electron affinity decreases
electron affinity
the amount of energy that is released when a single atom gains an electron at gaseous phase
