Name Symbol Electron Configuration Scandium S Titanium TVanadiuChromium C Manganese MIron F Cobalt C Nickel Copper C 10 4 s 1 Zinc Z 10 4 s 2 As Chromium and Copper are in the fourth period we would expect it to follow the same pattern as the other elements in the same periods as in the 4 s sub shell is filled first rather than the 3 d sub shell. Chromium (Cr) Expected Electronic ConfigurationActual Electron Configuration The arrangement [Ar] 3 d 5 4 s 1 is more stable than the arrangement [Ar] 3 d 4 4 s 2 because the half filled 3 d 5 sub level is more stable than the expected 3 d 4. Copper (Cu) Expected Electron ConfigurationActual Electron Configuration 10 4 s 1 The Arrangement [Ar] 3 d 10 4 s 1 is more stable than the expected [Ar] 3 d 9 4 s 2 because the complete 3 d 10 sub shell is more stable the incomplete 3 d 9 sub shell. Only when the electrons are filling that the 4 s orbital is at a lower energy level than the 3 d. But once the electrons are actually in their designated shell the energy order changes and the 4 s electrons now have a higher energy level than the 3 d.
And because the electrons in the highest energy level are removed first when ions are formed, the 4 s electrons will be removed first. Ni 2+Cr 3+Zinc Zn only forms Zn 2+ ions as it has full 3 d sub shell and the 3 d 10 arrangement is a very stable arrangement. Manganese The most stable ions for manganese are the Mn 2+ ad the Mn 7+. This is because it has a structure of [Ar] 3 d 5 4 s 2. This means it is capable of losing either just the 4 s electrons in which case it forms the Mn 2+ ion or all of the 3 d and the 4 s electron in which case it forms the Mn 7+. The high level of stability is because of the half filled 3 d sub level in Mn 2+ or the full 3 p sub level in Mn 7+.
Iron Out of the two ions (Fe 2+ and Fe 3+) formed by iron the more stable one is the Fe 3+. This is because Fe has the electronic structure [Ar]3 d 6 4 s 2 and the ion is more stable when it loses three electrons to form the Fe 3+ ion ([Ar] 3 d 5) as opposed to the [Ar] 3 d 6 structure present in the Fe 2+ ion. Titanium and Scandium Ions are most stable when they have a full or half filed outer shell. This means both Ti and Sc form stable ions with an electronic configuration of 3 s 2 3 p 6. This means Sc and Ti lose 3 and 4 electrons respectively hence forming the Sc 3+ and the Ti 4+ ions. o web 5/HTML%20 Files / transition elements/7.
5. 2 Transition Elements Notes A. htm o web web Form 7 Chemistry – D. R. Barns-Graham Seventh Form Chemistry – Alex Eames and Graeme Abbot to Miscellaneous As Level worksheets and Labs.