Paper 3 : C1 + C2 + C3 + C7 Flashcards
What is an isotope?
Atom with the same atomic number and different mass number
How did Geiger and Marsden contribute to ideas about the structure of the atom?
Fired alpha particles at gold
Some alpha particles rebounded
Led to the idea that atoms have a nucleus
How did JJ Thompson contribute to atomic theory?
He discovered the electron
How did Bohr contribute to atomic theory?
He suggested that electrons occupy energy levels
Describe metallic bonding
Attraction between positive metal cations
And delocalised electrons
Why do metals conduct electricity?
They have delocalised electrons
Why do ionic compounds conduct electricity when molten or in solution but not as a solid?
In a solid ions cannot move
When dissolved or molten the ions can move
Why do ionic compounds have high melting points?
Strong attraction between oppositely charged ions
Why do metals have high melting points?
Strong attraction between positive ions and delocalised electrons
Why can non-cross linked polymers be stretched easily?
Weak intermolecular forces
Polymer molecules can slide over each other
Why do cross-linked polymers have high melting points?
Strong crosslinks between the polymer molecules
Why is diamond used in cutting tools?
It is hard and it has a high melting point
Why is graphite slippery?
Weak bonds between the layers
Layers can slide over each other
Why is diamond used in jewellery?
Lustrous and transparent
Why do giant covalent compounds have high melting points?
Strong covalent bonds
Need lots of energy to break the bonds
