electrons and the periodic table Flashcards
(22 cards)
the larger the value of quantum number the …
the higher the energy level and the further the shell is from the nucleus
what happens as you move from one shell to the next ?
the further the shell is from the nucleus
in which order does the sub-shell energy increase
in the order s, p , d ,f
what happens when you go beyond the 3rd sub-shell ?
- the 4s energy level is below the 3rd energy level
- the 4s - orbitals fill before the 3-d orbitals
how does the sub-shell orbitals fill for an atom of potassium ?
1s2 , 2s2, 2p6 , 3s2 , 3p6 ,4s1
how does the electrons fill in terms of from 3rd sub-shell to 4th subshell and why ?
- the 4s sub-shell has a lower energy level than the 3d sub-shell
- the 4s-orbital fills before the orbitals in the 3d sub-shell
- the 4p orbital starts to fill after the 3d orbital is full
how is the periodic table structured in blocks ?
2 , 6, 10 , 14
what does the pattern mirror ?
the sub-shells that are being filled
how can one easily see the pattern ?
by dividing the periodic table into blocks
give an example of the ‘pattren’
O is the 4th element in the 2p block –> 2p4
O has the electron configuration 1s2 , 2s2 ,2p4
what can happen with atoms with many electrons ?
the electron configuration notation can become very lengthy
how are atoms often abbreviated ?
by basing the inner shell configuration on the noble gas that comes before the element in the periodic table
what does the shortening of the electron configuration allow us to do ?
concentrate on the important outer shell portion of the electron configuration
what are the outer shell portion of an element show ?
they are responsible for the chemical character of the element
what us the noble gas that becomes before
Li , Na, K
Li- helium
Na- Neon
K- Argon
what happens when a positive ion is formed in terms of electron configuration ?
- electrons are removed from the highest energy orbitals
what happens when a negative ion is formed in terms of electron configuration ?
- electrons are added to the highest energy orbitals
show what happens to Mg and a Mg 2+ ion
Mg - 12 - 1s2 , 2s2 , 2p6 , 3s2
Mg 2+ - 1s2 , 2s2 , 2p6
show what happens to Cl and Cl-
Cl - 1s2 , 2s2 , 2p6 , 3s2 , 3p5
Cl- - 1s2, 2s2 , 2p6, 3s2 , 3p6
what is the exception to this rule ?
the elements Sc to Zn at the top of d-block in the PT
how does this exception work ?
- as 4s and 3d energy levels are close together
- after 4s orbital has been filled
–> actually at a slightly higher energy than the 3d level
SO 4s electrons are lost before 3d electrons
first in , first out
what is the difference between Fe 2+ ion and Fe in electron configuration ?
Fe - 1s2 2s2 2p6 3s2 3p6 4s2 3d6
Fe2+ - 1s2 2s2 2p6 3s2 3p6 3d6
