2.1.1 [Metallic bonding] Flashcards
What is Metallic bonding?
Metallic bonding consists of a lattice of positively charged ions surrounded by a sea of delocalised electrons. There are very strong electrostatic forces of attraction between these oppositely charged particles electrons are delocalised because free to move throughout the structure.
What are the physical properties of metals?
.High melting temperatures
.Good electrical conductivity
.Good thermal conductivity
.Malleability
.Ductility
How does sizes of charge and size of ions affect the attraction between the particles?
The greater the charge on the positive ion the stronger the attractive force as more electrons are released into the sea
Ions that are larger in size like barium producer a weaker attraction due to their greater atomic radius
Why do metals have high melting temperatures?
In order to melt a metal need to overcome forces of attraction between the nuclei of the cations and delocalised electrons to extent where cations can move free around the structure. Metals have giant lattice structure many of these forces must be overcome. Large energy required.
Number of delocalised electrons per cation helps to determine melting temp
Group 1 metals have low melt temp
Group 2 metals have high melting points
Metals in d block have highest as most delocalised electrons per ion.
Smaller the cation closer delocalised electron greater attraction between nucleus and delocalised electrons greater melting temp
How do metals conduct heat?
Free moving delocalised electrons pass kinetic energy along the metal
The cations closely packed pass kinetic energy from one cation to another
How are metals Malleable and ductile?
Metals can be hammered or pressed into different shapes (Malleable). They can also be drawn into wires (ductile) Both of these properties depend on the ability of the delocalised electrons and the cations to move through structure of the metal.
