High School Chemistry/Transition Elements

The main group elements are actually in two groups: the s block and the p block. These two, let's call them sub groups, are separated in the Periodic Table by a special group of highly colorful compounds known as the transition metals. The transition metals represent groups 1B through 8B of the diagram below and are formed as electrons are filling in the d orbitals. This is why they are referred to as the d block. We will look at all of this in the lesson that follows.


 * Periodic Table structure.svg

Lesson Objectives

 * Define transition metals.
 * Explain the relationship between transition metals and the d sublevels.
 * State the periods that contain transition metals.
 * Write electron configurations for some transition metals.

Elements Whose Atoms are Filling d Sublevels
The elements in groups 1B through 8B (also known as 3 through 12) are called the transition metals. Sometimes this block of elements are referred to as the d block. They are called d block elements because the electrons being added in this block of elements are being added to the d orbitals. Look at the electron configurations for Scandium (Sc), Titanium (Ti), and Vanadium (V), the first three transition metals of the first row in the d block.




 * $$_{21}\text{Sc}$$: || $$1s^22s^22p^63s^23p^64s^23d^1$$
 * $$_{22}\text{Ti}$$: || $$1s^22s^22p^63s^23p^64s^23d^2$$
 * style="text-align:right;"|$$_{23}\text{V}$$: || $$1s^22s^22p^63s^23p^64s^23d^3$$
 * }
 * style="text-align:right;"|$$_{23}\text{V}$$: || $$1s^22s^22p^63s^23p^64s^23d^3$$
 * }

Notice that as the atomic number increases, the number of electrons in the d sublevels increases as well. This is why the phrase d block was started for the transition metals. The transition metals were given their name because they had a place between Group 2A (now Group 2) and Group 3A (now Group 13) in the main group elements. Therefore, in order to get from calcium to gallium in the Periodic Table, you had to transition your way through the first row of the d block (Sc → Zn). To get from strontium to indium, you had to transition your way through the second row of the d block (Y → Cd).


 * {| class="wikitable" style="text-align:center;"

!scope="row"|Group !scope="col"|3 !scope="col"|4 !scope="col"|5 !scope="col"|6 !scope="col"|7 !scope="col"|8 !scope="col"|9 !scope="col"|10 !scope="col"|11 !scope="col"|12 !scope="row"|Period 4 !scope="row"|Period 5 !scope="row"|Period 6 !Period 7
 * Sc
 * Ti
 * V
 * Cr
 * Mn
 * Fe
 * Co
 * Ni
 * Cu
 * Zn
 * Y
 * Zr
 * Nb
 * Mo
 * Tc
 * Ru
 * Rh
 * Pd
 * Ag
 * Cd
 * La
 * Hf
 * Ta
 * W
 * Re
 * Os
 * Ir
 * Pt
 * Au
 * Hg
 * Ac
 * Rf
 * Db
 * Sg
 * Bh
 * Hs
 * Mt
 * Ds
 * Rg
 * Cn
 * }

One interesting point about the transition metals that is worth mentioning is that many of the compounds of these metals are highly colored and used in dyes and paint pigments. Also, metallic ions of transition elements are responsible for the lovely colors of many gems such as jade, turquoise and amethyst.

Write the electron configuration code for Fe.

Solution:

26Fe: 1s22s22p63s23p64s23d6

Transition Metals Occur in Periods 4 – 7
As stated before, transition metals are also called the d block because they fill up the d sublevels. Therefore, the first three periods do not have transition elements because those energy levels do not have d sub-shells. The transition metals have atomic numbers greater than 20 because the first d electron appears in element #21 after the 1s, 2s, 2p, 3s, 3p, and 4s orbitals are filled.

Lesson Summary

 * Transition metals are those from the d block or those from Groups 3 through 12.
 * Compounds of transition metals typically are those that are highly colored.
 * Transition metals are found in Periods 4 through 6.

Review Questions

 * 1) Write the electron configuration for zirconium, Zr.
 * 2) How many valence electrons does zirconium, Zr, have?
 * 3) Write the noble gas electronic configuration for platinum, Pt.
 * 4) How many valence electrons does platinum, Pt, have?
 * 5) Why do the d block elements only start in the fourth period?
 * 6) What do copper, silver, and gold have in common as far as their electron configuration?
 * 7) Which of these is the electron configuration for nickel?
 * (a) [Kr]3d84s2
 * (b) [Kr]3d10
 * (c) [Ar]3d84s2
 * (d) [Ar]3d10
 * 1) How many d electrons are there in the electronic configuration for ruthenium?
 * (a) 0
 * (b) 6
 * (c) 7
 * (d) 17
 * 1) Write the electron configuration for Iridium, Ir.
 * 2) What are the valence electrons for Iridium, Ir?
 * 3) Write the noble gas electron configuration for mercury, Hg.
 * 4) How many valence electrons does mercury, Hg, have?

Vocabulary

 * transition metal
 * Groups 3 through 12 (or the d block) of the Periodic Table.