what do the mass number and atomic number represent?
mass- number of protons and neutrons. atomic- number of protons
1 of 21
what are the relative masses of the 3 types of particles in an atom
proton- 1, neutron- 1, electron- 0.0005
2 of 21
What is a compound?
where two or more different elements are chemically combined
3 of 21
define the term isotope
different atomic forms of the same element, where they have the same number of protons but different number of neutrons
4 of 21
Describe the process of ionic bonding
metal atoms give away electrons to form positively charged ions and non metal atoms gain electrons to form negatively charged ions. the electrostatic attraction between the oppositely charged ions hold the ions together in a giant ionic lattice
5 of 21
describe the structure of a crystal of sodium chloride
giant ionic lattice where strong forces of electrostatic attraction hold together the positively charged sodium ions and the negatively charged chloride ions
6 of 21
List the main properties of ionic compounds
high melting and boiling point, only conducts electricity when molten or dissolved in water
7 of 21
What is covalent bonding?
where non-metal atoms share electrons with each other to both gain a full outer shell structure
8 of 21
What are the two types of covalent structures and give examples
giant covalent structure (lattice)- diamond. Or simple molecular substances e.g. water
9 of 21
list two properties of metals and how metallic bonding causes these properties
can conduct heat and electricity- metallic structure contains delocalised electrons free to move throughout the structure and carry the charge. High melting points- strong electrostatic forces of attraction between +ve cations and -ve electrons.
10 of 21
Explain why alloys are harder than pure metals
alloys contain different sized atoms, so they disrupt the regular layers of the metal making it harder for the layers to slide over each other to bend the metal, so the metal is harder
11 of 21
Give an example of a 'smart' material and how it behaves
nitinol- shape memory alloy. when cool it can be bent, but when heated it returns to its original shape.
12 of 21
what are nanoparticles? give two different applications of them
nanoparticles are particles that contain only roughly a few hundred atoms. they can be used as catalysts or in cosmetics
13 of 21
explain the difference between thermosetting and thermosoftening polymers
thermosetting polymers do not melt when heated but thermosoftening polymers easily melt when heated
14 of 21
define relative atomic mass and relative formula mass
relative atomic mass- a way of saying how heavy something is compared with the mass of an atom of carbon-12 (usually just the mass number). relative formula mass is all the relative atomic masses added up in a compound
15 of 21
what is the link between moles and relative formula mass?
the relative formula mass of a substance in grams is one mole of that substance. e.g. Ar of iron is 56 so one mole of iron weighs 56g
16 of 21
what is an empirical formula?
the ratio of elements in a compound in its simplest form
17 of 21
describe three factors that can reduce the percentage yield of a reaction
1. the reaction is reversible. 2. some of the liquid product is lost in filtering. 3. unexpected reactions can occur which use up reactants
18 of 21
explain how paper chromatography can be used to analyse the dyes in a brown sweet
extract the colour from the food sample by placing it in a cup with some solvent. put the spot of colour on a pencil baseline of filter paper and place into a beaker with some solvent. the different dyes will run and form spots in different places
19 of 21
briefly describe how gas chromatography works
an inert gas is used to carry substances through a a column packed with solid material. the different substances will travel through the column at different speeds and so leave the column separately and then identified by retention time
20 of 21
how do you work out relative formula mass from mass spectrometry
you look at the peak furthest to the right in a mass spectrum called the molecular ion peak- this gives you relative mass
21 of 21
Other cards in this set
Card 2
Front
what are the relative masses of the 3 types of particles in an atom
Comments
No comments have yet been made