15- Transition metals Flashcards
Why does the 4s subshell fill before 3d?
Although closer to the nucleus, the 3d subshell has a higher energy level and so electrons fill the 4s first.
What two transition metals break the trend for electron configuration and why?
Chromium and copper, as the stability associated with half filled and filled subshells means chromium is more stable with a [Ar]3d5 4s1. and copper is more sable with [Ar]3d9 4s2, as it leads to an overall more even spread of charge around the nucleus.
Which sub shell is the first electron lost from by transition metals? Why?
The 4s sub-shell. Once the 3d subshell is occupied, it repels the 4s electrons to a higher energy level.
Differences between transition metals and scandium and zinc?
Scandium and zinc have only one oxidation state each, 3+ and 2+ respectively, wheras transition metals have more. They are also usually white, wheras the transition metals are usually coloured. They also show little catalytic activity.
Define a transition metal.
An element that has one or more stable ions with incompletely filled d orbitals.
Characteristics of transition metals?
Hard, high mp and bp, variable oxidation states, coloured ions in solution, act as catalysts as compounds and elements, form complex ions.
What is a ligand?
A molecule or anion bound to the central metal ion in a complex ion by coordinate bonding.
What is a complex ion?
An ion in which a number of molecules or anions are bound to a central metal cation by coordinate bonds.
What is coordination number?
Number of coordinate bonds to the metal ion from the surrounding ligands.
What shapes do complex ions form?
Octahedral, tetrahedral, square planar and linear.
How does oxidation relate to splitting and absorbtion.
Higher charge leads to greater splitting and absorption at higher frequencies/energies.
How do ligands affect splitting?
More ligands means more splitting and greater energies of absorption.
How does coordination number affect splitting?
Higher number means more splitting.
How to name complex ion?
- Number of ligands
- name ligands with name ending in -o for anions
- Name central metal ion, normal name for positive/neutral, latin for negative.
- Write oxidation for central metal ion.
Types of ligand?
Mono bi and multi dente ligands form 1,2 and 3+ dative covalent bonds
What is a chelate?
A complex ion involving multidente ligands.
