3.3- METALLIC BONDING Flashcards
What are metals?
shiny elements made up of atoms that can easily lose up to three outer electrons, leaving positive metal ions
What can atoms in a metal element not do?
transfer electrons
When can atoms of an element transfer electrons?
if there’s a non-metal atom present to receive them
What happens to the outer main levels of a metal element?
outer main level of atoms merge
What does it mean for the outer electrons as the outer main level of atoms merge in a metal element?
outer electrons no longer associated with any one particular atom
What is a simple picture of metallic bonding?
metals consist of a lattice of positive ions existing in a “sea” of outer electrons
What is the “sea” of electrons described as?
delocalised electrons
What does delocalised electrons mean?
they’re not tied to a particular atom
What do the positive ions tend to do to one another?
positive ions tend to repel one another
What is the repulsion of the positive ions balanced by? (metallic bonding)
electrostatic attraction of positive ions for negatively charged “sea” of delocalised electrons
What does the number of delocalised electrons depend on? (metallic)
depends on how many electrons have been lost by each metal atom
Where does the metallic bonding spread throughout?
spreads throughout so metals have giant structures
What can delocalised electrons do?
move throughout the structure
As electrons are able to move throughout the structure, what does this explain in metals?
why metals are such good conductors of electricity
From where does the electron join the electron sea?
electron from the negative terminal of the supply joins the electron sea at one end of a metal wire while at the same time a different electron leaves the wire at the positive terminal
Why are metals good conductors of heat?
they have high thermal conductivites
What is partly responsible for metals having a high thermal conductivity?
sea of electrons is partly responsible for this, with energy also spread by increasingly vigorous vibrations of closely packed ions
In general what does the strength of any metallic bond depend on? (2)
charge of ion
size of ion
How does charge of the ion affect the strength of the metallic bond?
greater the charge on ion, greater the number of delocalised electrons + stronger the electrostatic attraction between positive ions and electrons
How does size of the ion affect the strength of the metallic bond?
smaller the ion, closer the electrons are to positive nucleus + stronger the bond
What do metals tend to be? (strength)
strong
What explains the metals being strong?
delocalised electrons
How do the delocalised electrons explain why metals are strong?
extend throughout solid so there are no individual bonds to break
What is it called when metals can be beaten into shape?
metals are malleable
What is it called when metals can be pulled into thin wires?
metals are ductile
After a small distortion of a metal how is the shape retained?
each metal ion still in exactly the same environment as before so shape retained
Do metals have a high or low melting and boiling points?
high melting and boiling points
Why do metals have a high melting and boiling points?
they have giant structures
What is there between the metal ions and the delocalised sea of electrons?
strong attraction between metal ions and delocalised sea of electrons
What is made difficult as there is a strong attraction between the metal ions and delocalised sea of electrons?
makes the atoms difficult to separate
