chapter 24 Flashcards
properties of metals in the first row of transition metals
high melting and boiling points
conduct electricity when solid and liquid
insoluble in water
which subshell between the 3d and 4s subshells lose electrons first, and also get filled first
the 4s subshells
d-block elements
elements with their highest energy electrons in d-orbitals
why are chromium and copper special compared to other transition elements
because they have only one electron in their 4s subshell, as they promote the other electron to the 3d subshell
why do chromium and copper have only one electron in their 4s subshell
because a fully filled 3d subshell in Cu, and a half filled 3d subshell in Cr provides stability to the atoms of Cu and Cr.
why are atoms with only one electron in their orbitals more stable than those with fully filled orbitals
because the fact that there is only one electron in each orbital minimises repulsion in the atom, therefore providing stability
transition element
d-block element that forms at least one ion with a partially filled d-orbital
why are scandium and zinc not classed as transition elements although they are d-block elements
this is because, they do not form an ion with a partially filled d-orbital, and so they do not follow the definition of a transition element
Scandium has no electrons in it’s d-subshell when it forms the Sc^+3, while zinc has a fully filled d-subshell when it forms the Zn^+2 ion
Zinc and Scandium form only one ion respectively
what are these ions
Zn^+2
Sc^+3
4 properties of transition metals
Give examples
they form compounds in which the transition element has different oxidation states (in FeCl2, Fe has oxidation state of +2, but in FeCl3, Fe has oxidation state +3)
the form coloured compounds ( for example manganese forms manganate, which is purple in colour)
the elements and their compounds can act as catalysts ( for example, Iron is a catalyst in the haber process)
they form complex ions in solution
what does the oxidation state of +2 in transition elements correspond to
the loss of 4s electrons
function of a catlyst
to provide an alternative pathway for a reaction to occur, by lowering the activation energy
transition metals are used as catalysts for numerous reactions, true or false
true
heterogeneous catalysts
catalysts that are in a different state to the reactants
adsorption
this is when reactant molecules form weak bonds to the catalyst surface
