Flashcards
CHEMISTRY UNIT 2
Cards in this deck (32)
- 1What is the mass number in an elementtotal number of protons and neutrons
- 2What is the atomic numberHow many protons there are
- 3How do you work out the number of neutronsAtomic number - mass number
- 4What are compoundsChemically bonded elements
- 5Define 'isotope'Isotopes are different atomic forms of the same element which have the same number of protons but different number of neutrons
- 6Which groups in the periodic table are most likely to form ionsGroups 1 + 2 and 6 + 7
- 7Which groups are metals and form positive ions when electrons are lost1 + 2
- 8What non-metal groups form negative ions when electrons are gained6 + 7
- 9What are ionic compound made up of in chargesPositively charged part and a negatively charged part that have the overall charge of 0
- 10What is ionic bondingIt is the loss of gain of electrons to form ions which are strongly attracted to eachother
- 11What shells want to get rid of electronsShells with one or two electrons on their outer shell
- 12What shells want to gain extra electronsShells that have 6/7 electrons
- 13Fact:Ionic compounds always have a giant ionic lattice
- 14Fact:Strong forces of electrostatic attraction are acting in ionic compounds
- 15What are the properties of ionic compoundsHigh melting point, high boiling point due to ion attraction
- 16What is covalent bondingCovalent bonds are the sharing of electrons with other atoms
- 17Fact:Atoms form very strong covalent bonds to small molecules of several atoms
- 18Properties of simple molecular substancesWeak intermolecular forces therefore means low melting and boiling point, usually gases or liquids
- 19Giant covalent structures propertiesHigh melting and boiling points also there's no conduction of electricity except graphite
- 20Fact:Giant covalent structures are similar to giant ionic structures (lattices) except no charged ions
- 21Diamond structureEach carbon atom forms 4 covalent bonds -rigid structure. Hardest natural substance- used for drill tips
- 22Graphite StructureEach carbon atom has 3 covalent bonds and creates layers which slide over each other. There's weak intermolecular forces, graphite can conduct electricity and heat as each carbon atom has 1 de-localised electron
- 23Silicon Dioxide StructureWhat sand is made of. It's one giant structure of silicon and oxygen
- 24What are free electronsDue to electrons on outer shells they are able to move, there are strong electrostatic forces of attraction
- 25What is an alloyAn alloy is a mix of two or more metals than can acquire certain properties
- 26Why are the sizes of atoms different in alloysDue to different elements in the alloy and this creates distorted layers of atoms that are hard to slide therefore bend
- 27What is 'Nitinol'It is a smart material. Shape memory alloys can return to their original shape when deformed- braces frames
- 28What are 'fullerences'Carbon molecules shaped like 'hollow balls' , they can make 'nanotubes' and have covalent bonds which is used to reinforce graphite tennis rackets
- 29Uses of nanosciencehuge surface area to volume ratio so they're used for industrial catalysts, conducts electricity so computer chips
- 30What are thermosoftening polymers?They don't have cross links between chains and the forces are easy to overcome, easy to melt and remould. WEAK FORCES
- 31What's thermosetting polymersStrong intermolecular forces that have cross links in-between chains and it doesn't melt when heated.
- 32How are the properties of polymers affectDepends on what they're made from and the conditions- low density or high density
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- Flashcards on CHEMISTRY UNIT 2, created by Anna Waldron on 15/04/2015.
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- Anna Waldron
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