Topic 2 Flashcards
(39 cards)
how are ions made
ions are made when electrons are transferred
what happens when non metals form ions
they gain electrons into their outer shell to form negative ions
which groups are most likely to form ions
1&2 and 6&7
what is covalent bonding
it is when non-metals bond together and share pairs of electrons
why are covalent bonds strong
the positively charged nuclei of bonded atoms are attracted to the shred pair of electrons by electrostatic forces making them strong
What are the states of matter and there state symbols?
Solid-s
Liquid-l
Gas-g
Aqueous solution-aq
what does metallic bonding involve?
metallic bonding involves delocalised electrons
how can metallic bonding occur
The electrons on the outer shell are delocalised and therefore there are strong forces of electrostatic attraction between positive metal ions and the shared negative electrons
What does the structural formula show?
It shows the bonds between atoms in a molecule
What happens in the structural formula?
each atom is shown by its chemical symbol
each covalent bond is shown as a straight line
what are atoms bonded together by in giant covalent structures?
Strong covalent bonds
why do covalent structures have a high melting and boiling points?
Because lots of energy is needed to break down the strong covalent bonds between atoms
Why don’t giant covalent structures conduct electricity?
they don’t contain charged particles and therefore don’t conduct electricity even when molten
What are the main examples of giant covalent structures and what are they made of
diamond and graphite
which are made from carbon atoms and silicon dioxide(silica)
What are polymers?
they are long chains of repeating units
What is a polymer?
lots of small units are linked together to form a molecule
What are all the atoms in a polymer joined by?
they are joined by strong covalent bonds
why are most polymers a solid at room temperature?
the intermolecular forces between polymer molecules are larger then simple covalent molecules so more energy is needed to break them down
Why do polymers have a lower boiling point the ionic or giants molecular compounds?
they intermolecular forces are weaker then ionic or covalent bonds
what are fullerenes and how do nanotubes play into this?
they are forms of carbon dioxide and inculde nanotubes
what are nanotubes?
long cylindrical molecules made from carbon atoms which are joined together by covalent bonds
What is an allotrope?
different structural forms of the same element in the same physical state
What are carbons 3 allotropes?
diamond, graphite and graphene
What is diamond?
a giant covalent structure, each carbon atom haa 4 covalent bonds
