Transition Metals - electron config. and variable oxidation states Flashcards
Define a transition element
A D-block element that can form at least one stable ion with a paertialy filled d-subshell.
how many electrons can a D subshell hold
10 electrons
in period 4 how many elements are transition metals.
- which ones arent and why
8 are transition metals.
- Scandium and Zinc are not TMs, this is becuase they don’t form a stable ion with a partially filled d-subshell.
How do the electrons of TMs fill up the sub shells and why
they start off by filling up the 4s orbittal first, and they tend to fill up singly before doubling up, this is because electrons repels each other, so cos they have low energy they fill up individiually as much as they can and then double up.
what are the two annomalies. what are their electron configs and why are they like that (electrons don’t like sitting next to each other - repel)
- Chromium = [Ar] 3d5, 4s1 = the electron that supposed to be in the 4s orbital shifts to the last part of the 3d orbital, they do this to form a half filled subshell which gives them more stability.
- Copper = [Ar] 3d10, 4s1 = Here having a full 3d subshell gives it more stability than having 3d9 and 4s2 configuration.
what is the main basis of the TMs characterisitics
the electron configuration
- what stable ion can Sc form ?
- whats the electron config of Sc and explain why it can’t be a TM
- Sc can only form one stable ion = Sc3+
- the electron config of Sc is [Ar] 3d1, 4s2 = this does have a partially filled d-subshell but the definition of a TM says it should be a stable ion with a partially filled d-subshell
- the electron config of Sc3+ = [Ar] 3d0, 4s0 = which isnt partially filled.
- what stable ion can Zn form ?
- whats the electron config of Zn and explain why it can’t be a TM
- Zn can only form one stablw ion = Zn2+
- the electron configuration of Zn is = [Ar] 3d10, 4s2
this has a full d-subshell, so can’t be a TM. - Zn2+ = [Ar] 3d10, 4s0 = the stable ion doesnt have a full d-subshell as it loses the 4s electrons first.
what orbital does the electrons of TMs lose first
they lose the 4s orbitals electrons first then the 3ds - subshell.
List the properties of TMs
they have specific properties which include variable oxidatin states, formation of coloured ions, act as catalysts and their complex formations.
what are the colours of the compounds formed of Sc and Zn and why
they both form white compounds as they have no electrons in the d-subshell.
why do TMs have variable oxidation states. and what does it result in
TMs have their electrons sitting in 4s and 3d eneergy levels, these two very close to each othe.
- as a result electrons are gained and lost using a similar amount of energy when they form ions.
- so they have variable OS.
what ions can vanadium form, and what is the OS of V in each one and what colour solution does each one form when dissolved in water ?
VO2^+ Oxidation state +5 - yellow solution
VO^2+ Oxidation state + 4 - blue solution
V^3+ Oxidation state + 3 - green solution
V^2+ Oxidation state + 2 - violet solution
whats the colour of the sol formed from V^3+
green solution
whats the colour of the sol formed from V^2+
violet solution
whats the colour of the sol formed from VO^2+ (also known as V() vanadate ions
blue solution
whats the colour of the sol formed from VO2^+
yellow solution.
ions formed by Chromium
Cr^3+
Cr2O7^2-
whats the colour of the sol formed from Cr^3+
when normally substituted = green
but when surrounded by 6H2O = violet
whats the colour of the sol formed from Cr2O7^2-
Orange solution
ions formed by manganese
Mn^2+
MnO4^-
MnO4^2-
whats the colour of the sol formed from Mn^2+
pale pink
whats the colour of the sol formed from MnO4^-
Purple
ions formed by iron
Fe^2+
Fe^3+
whats the colour of the sol formed from Fe^2+
pale green solution
whats the colour of the sol formed from Fe^3+
when surrouned by 6 water ligands they are purple.
- but the sol may appear yellow instead cos of a hydrolysis reaction.
whats the colour of the sol formed from Nickels only stable ion
Ni^2+ = green solution
- whats the colour of the sol formed from Copper only stable ion
Cu2+ = blue
whats the colour of the sol formed from MnO4^2-
green
what can be used to reduce Vanadium ions - VO2^+
Zinc
what order of ions and colours does the vanadium ion reduce to when added with zinc in an acidic solution
VO2^+ = yellow ->
2VO2^+(aq) + Zn(s) + H^+ => 2VO^3+(aq) +Zn^2(aq)+ +H2O (l)
-> VO^2+ = blue ->
-> V^3+ = green ->
-> V^2+ = violet
