topic 1 - atomic structure and the periodic table Flashcards
what’s the radius of an atom
0.1 nanometres
what is the mass number
number on the top, tells you total number of protons and neutrons in the atom
what is the atomic number
number on bottom, tells you number of protons there are
how do you work out the number of neutrons in an atom
subtract the atomic number from the mass number
an atom of gallium has an atomic number of 31 and a mass number of 70. give number of protons, neutrons and electrons in the atom
p12 q1
what is an isotope
isotopes are different forms of the same element which have the same number of protons but a different number of neutrons.
isotopes have the same atomic number but a different mass number
what’s the formula for relative atomic mass
relative atomic mass(Ar) = sum of (isotope abundance x isotope mass number) divided by sum of abundances of all isotopes
a substance consists of atoms which all have the same number of protons and electrons but different numbers of neutrons explain why this substance is an element
p13q1
what is a compound
a compound is a substance formed from two or more elements, the atoms of each are in fixed proportions throughout the compound and they’re held together by chemical bonds
what’s a mixture
Two or more substances that are not joined together. The substances can be elements, compounds, or both.
what is a pure substance
a pure substance consists only of one element
or one compound
what is filtration
Filtration is used to separate an insoluble
solid from a liquid. It is useful for separating sand from a mixture of sand and water, or
excess reactant from a reaction mixture.
Why does iodine have a higher boiling point than chlorine?
The forces between iodine molecules are stronger
Chlorine displaces bromine from bromide ions.
Cl2 + 2Br- → 2Cl- + Br2
What happens in this reaction?
Bromide ions lose electrons and are oxidised
Group 1 elements have ______________ melting points.
Group 1 elements are ________ metals.
Group 1 elements have low melting points.
Group 1 elements are soft metals.
Why is aluminium positioned in group 3 of the periodic table?
It has three electrons in its outer energy level/outer shell.
Substance Boiling point
Ethanol 78°C
Water 100°C
Use data from table 1 to explain why ethanol and water can be separated using fractional distillation.
Ethanol has a lower boiling point than water. [1 mark]
On heating, ethanol vapour leaves the mixture of liquids first. [1 mark]
The ethanol vapour can be cooled and condensed separately. [1 mark]
Describe how a sample of copper chloride crystals could be made from copper carbonate and dilute hydrochloric acid
Add excess copper carbonate to dilute hydrochloric acid. [1 mark]
Filter. [1 mark]
Heat filtrate to evaporate some water. [1 mark]
Leave to cool. [1 mark]
Group 1 of the periodic table contains the alkali metals lithium, sodium and potassium.
The alkali metals show a pattern in their reactivity with water.
This pattern is shown when small pieces of lithium, sodium and potassium are added separately to water.
Describe the reactions and explain the pattern in reactivity.
Description:
effervescence/fizzing/bubbles
float/on surface
move
produce hydrogen (may be shown in word or balanced equation)
an alkaline/metal hydroxide solution (may be shown in word or balanced equation)
gets smaller/disappears/dissolves
reactivity increases with increasing atomic number/down the group/potassium effervesces more than sodium and lithium/potassium moves faster than sodium or lithium
sodium and potassium melt/form a (silver-coloured) ball
hydrogen burns when potassium/ sodium react
potassium gives a lilac flame/sodium gives a yellow flame
universal indicator added to water turns blue/purple
Explanation:
(group 1 metals) react by losing one electron
electron is more easily lost with increasing atomic number/down the group
electron/ outer shell is further away from nucleus/atomic radius increases/there are more electron shells with increasing atomic number/down the group
more shielding (of outer electron)/less attraction between nucleus and outer electron/ more shells between outer electron and nucleus with increasing atomic number/down the group
which method of distillation would you use to separate liquids with similar boiling points
fractional distillation
what is the difference between a compound and a mixture
what is the name of the pattern formed from carrying out paper chromatography
which method of separation is useful to separate an insoluble solid from a liquid
filtration
who discovered that the plum pudding model was wrong
who first devised an experiment that proved the existence of the neutron
why did mendeleev leave gaps in the periodic table
give three properties specific to transition metals
1) they can have more then one ion
2) often coloured compounds that contain them are colourful
3) they make good catalysts
state three trends as you go down group one
-increasing reactivity
-lower melting and boiling points
-higher relative atomic mass
state the products of the reaction of sodium and water
sodium + water = sodium hydroxide + hydrogen
state the differences between group one and transition metals for the following properties
1) hardness
2)reactivity
3)melting points
1) group one elements are much less dense, strong and hard than the transition metals
2) group one metals are much more reactive then transition metals
how do the boiling points of halogens change as you go down the group from fluorine to astatine
they increase
what is the charge of the ions that halogens form when they react with metals
1- ions
predict whether iodine is displaced by chlorine in a solution of potassium iodide
chlorine will displace iodine in an aqueous solution because potassium iodide is a salt- more reactive halogens replace less reactive ones
what is the trend in the boiling point as you go down group 0
the boiling points of the noble gases increase as you move down the group along with increasing relative atomic mass
why do the boiling points increase in noble gases as you go down group 0
the increase in boiling point is due to an increase in the number of electrons in each atom leading to greater intermolecular forces between them which need to be overcome.
