Topic 4 Flashcards
How does the presence of impurities affect the malleability of a metal?
They make the metal less malleable because the layers cannot slide over each other as easily
- Impurities are often different sizes to the cations within the metal structure so they disrupt the layers and prevent them from easily sliding over each other; the property that allows the metal to be malleable.
Is NH3 polar
yes
If aluminium is soft and malleable while raw tungsten is hard and brittle, which of the following statements is correct?
When you squeeze or press aluminium, it will bend easily
Which of the following period 3 metals has the strongest metallic bond: sodium, magnesium or aluminium?
Aluminium
- there are more electrons in the ‘sea’ of delocalised electrons. The aluminium ion has a higher charge than the sodium and magnesium ion, therefore, the strength of the attraction between the cation and delocalised electrons is stronger. The ionic radius of an aluminium ion is smaller than a sodium and magnesium ion which allows the ions to pack closer together. This is another factor that contributes to the stronger metallic bond.
What increases across a period?
first ionisation energy & electronegativity
why does electronegativity decreases down a group?
Atomic radius increases down a group
how are elements ordered in the periodic table?
in order of increasing protons
Ionic bond
An ionic bond is an electrostatic attraction between oppositely-charged ions
Electrostatic attraction:
is the force of attraction between opposite charges
Why will a cation be smaller than its original atom?
the cation loses its entire valence shell
Why does the anion increase in size?
because of the repulsion of the additional electrons
Polyatomic ions definition
ions that consist of more than one atom
