Physical Properties of Transition Elements (HL) (DP IB Chemistry): Revision Note

Physical properties of transition elements

What are transition metals?

• The definition of a transition metal is an element with an incomplete d-subshell or an element that can form at least one stable cation with an incomplete d-subshell

• This definition distinguishes them from d-block elements because scandium and zinc do not fit the definition

  • Sc only forms the ion Sc³⁺, configuration [Ar] 3d⁰

  • Zn only forms the ion Zn²⁺, configuration [Ar] 3d¹⁰

• The elements of the first transition series are therefore Ti to Cu

Where are transition metals on the Periodic Table?

• The transition metals are located in the d-block

  • Period 4: From Ti to Cu

  • Period 5: From Zr to Ag

  • Periods 6 and 7 are complicated by the presence of the f-block lanthanides and actinides 

Location of transition metals in the Periodic Table

Structure and properties of transition metals

• Like other metals, transition metals have a metallic lattice structure

  • Layers of positive ions within a sea of delocalised electrons

• Since the 3d and 4s subshells are so close in energy, the transition metals are able to delocalise their d-electrons to form metallic bonds

• This causes transition metals to have particularly good electrical conductivity and high melting points

Why do transition metals have high melting points?

• Transition metals form metallic bonds involving both s- and d-electrons

• The more delocalised electrons available, the stronger the electrostatic attraction between cations and the electron "sea"

  • The stronger forces of attraction result in a higher melting point as more energy is required to overcome them

• The Period 4 transition metals have higher melting points than Group 1 and Group 2 metals:

  • There is an exception to the lower melting points of s-block metals with a melting point of 1,287 ^oC for Be, due to the small size of a Be atom resulting in strong metallic bonding 

Melting point graph

Why do transition metals have high electrical conductivity?

• Transition metals have a large number of delocalised electrons

• Therefore, more electrons are able to move when a potential difference is applied

• This causes transition metals to have high electrical conductivity

• The three most conductive metals are: 

  1. Ag

  2. Cu, not that this is the most used metal in electrical cables due to a combination of cost and conductivity

  3. Au

• For more information about other characteristic properties of transition metals, see our revision note on the Characteristic Properties of Transition Elements