metals. chemistry
TRANSCRIPT
MetalsStructure and bonding
Table of contents• Metals• Metallic bonding & Metal’s structure• Giant Metallic Lattice• Properties• Place in periodic table
Metals--is a solid material (an element, compound, or
alloy) that is typically hard, opaque, shiny, and
features good electrical and thermal conductivity.
Metallic bonding & Metal’s stricture
Metallic bonding is occurs in Metals. It is the electrostatic attraction between positive metal ions and delocalized electrons.
A giant metallic lattice is a three-dimensional structure of positive ions and delocalized electrons, bonded together by strong metallic bonds.
Giant Metallic Lattice
A giant metallic lattice is often referred to as a
lattice of positive ions fixed in position and surrounded by a sea of electrons. The electrons are delocalized
and can move.
PropertiesThere are three main properties of giant metallic lattice structure:• High melting point and boiling point• Good electrical conductivity• Malleability and ductility
High melting point and boiling point
Most metals have high malting and boiling point.(except Mercury(Hg), its
melting point is -38.83 °C) The electrons are free to move throughout the
structure, but the positive ions remain where they are. The attraction between
the positive ions and negative delocalized electrons is strong. High
temperature are needed to break the metallic bonds are dislodge the ions from
their rigid positions within the lattice. Metals can have 600-1600°C melting
point.
Good electrical conductivity
Metals are good conductors of electricity. The delocalized electrons can move freely anywhere
within the metallic lattice. This allows the metal to conduct electricity, even in the solid state.
Malleability and ductility
Metals are ductile and malleable.
Ductile means: can be drawn out or stretched. Ductility permits metals to be
drawn into wires.
Copper Wire
Malleability and ductility
Malleable means: can be hammered into shape. Many metals can be
pressed into shapes or hammered out into thin sheets.
Malleability and ductility
The delocalized electrons are largely responsible for this properties. Because they can move, the
metallic structure has a degree of give, which allows atoms or layers to slide past each other.
Place in periodic table
Place in periodic table
Each vertical columns in periodical table is called a group, and contains element with similar properties. So almost all metals are in 1st , 2nd and 3rd groups.
Each horizontal row is called a period. Across each period, elements change from metal to non-metal. As you move down the Periodic Table, this change takes place further to the right. So, trends in properties can exist vertically down a group as well as horizontally across a period.