Top answers

Why do transition metals form coloured compounds?

Transition elements have 3d orbitals with the same energy level however when molecules/ligands form dative covalent bonds with a metal ion, the electron repulsion causes the 3d orbitals to split into lower a...
CC
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Identify which 2 of the following processes involve an exothermic change: melting, boiling, freezing, deposition and sublimation

An exothermic reaction involves an output of heat, so heat is lost overall. This would mean that boiling and melting are definitely not exothermic as they involving putting in heat. Freezing is an exothermic...
ES
Answered by Ellen S. • Chemistry tutor
6897 Views

What is the easiest way to calculate E cell values?

This is a calculation which students often find tricky. One fail-safe method for doing this calculation is considering E cell = E (reduced) - E(Oxidised). A more positive electrode potential means that a spe...
RD
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Why does the first ionisation energy increase across period 3?

The 1st ionisation energy is defined as the energy required to remove the outermost electron from one mole of gaseous atoms, forming one mole of gaseous 1+ ions. Moving from left to right the proton number i...
HP
Answered by Hamish P. • Chemistry tutor
2459 Views

The bond angle in a molecule of ammonia (NH3) is 107 degrees so why, when part of a transition metal complex is the bond angle 109.5 degrees.

Ammonia is based off a tetrahedral shape, the central Nitrogen atom has 4 valence (outer) pairs of electrons, 3 in covalent bonds with Hydrogen atoms and one "lone pair" which are not bonded. The t...
DW
Answered by Daniel W. • Chemistry tutor
69433 Views