C1 Atomic structure and periodic table Flashcards
define element
made up of the same type of atom and cannot be chemically split up further
define compound
two or more different atoms that are chemically bonded
define mixture
two or more atoms that are not chemically bonded
define empirical formula
The simplest ratio of atoms of each element in a compound
define empirical formula
The simplest ratio of atoms of each element in a compound
how do you calculate the empirical formula?
- count up number of each type of ion
- divide by the smaller number
- round to the nearest whole number
define solute
the name of what you dissolve
define solvent
the name of what you dissolve the solute in
define solution
the outcome of dissolving the solute in the solvent
define soluble
a name you give to a substance that can be dissolved
define insoluble
a name you give to a substance that cannot be dissolved
define solubility
the amount of solute that can be dissolved in 100g of solvent
through which experiment did John Thompson discover electrons mainly?
The Vaccum Tube
what did the experiment The Vacuum Tube show?
showed negatively charged particles flowing through an electrical current
what misconception did John Thompson think about electrons after the Vacuum Tube experiment?
he thought that electrons were part of the atom because they were much smaller and alike
what model of the atom did John Thompson make after the Vacuum Tube experiment?
the plum pudding model
describe the plum pudding model
had an area of positive space and had negative electrons randomly spotted in the middle
what experiment did Ernest Rutherford do?
the alpha particle scattering experiment
what was the alpha scattering experiment?
fired alpha particles (He2+ ions) at a piece of gold foil
what 4 things did Ernest Rutherford learn about the atom from the alpha particle scattering experiment?
- there is a positive nucleus in the middle
- electrons are around the nucleus
- the mass of the atom is concentrated at the middle
- most of the atom is space
how did Ernest know that there is a positive nucleus in the middle from the a.p.s experiment?
the particles were reflected/refracted by this and re-directed
how did Ernest know that the mass of the atom is concentrated in the middle from the a.p.s experiment?
some of the particles were deflected and some of them went straight through
describe what changes Bohr made to the nuclear model
he put electrons set distance from the nucleus and they are orbiting it, these are called shells/energy levels
describe 4 differences between the nuclear model and plum pudding model?
-plum pudding model has no nucleus
-in the ppm the mass was evenly distributed but in the nm its concentrated in the middle
-most of the nm is space but in the ppm there are no spaces
-in the ppm electrons are randomly plotted around but in the nm they are around the positive nucleus
why are lithium and sodium both in group 1?
they both have 1 electron in their outer shell
explain why sodium is more reactive than lithium
-sodium has more shells/its a bigger atom
-weaker force of attraction between outer electron and positive nucleus
-makes the outer electron easier to lose
give 2 observations you can see when potassium is added to water
-fizzing with bubbles
-the potassium floats on the water
explain why sodium oxide has a high melting point
- sodium oxide has a giant ionic structure
- have strong electrostatic forces of attraction between oppositely charged ions
- requires a lot of energy to break
give one limitation to using a dot and cross diagrams
doesn’t show the shape/ only two diminsional
give one limitation to using a dot and cross diagrams
doesn’t show the shape/ only two dimensional
define isotope
an atom of the same element that has the same number of protons but a different number of neutrons
what is the formula to find the relative atomic mass of an element with different isotopes?
(mass number x percentage) of isotope 1 +(mass number x percentage) of isotope 2 / 100
give the charge of a proton
positive charge +1
give the charge of a neutron
neutral charge 0
give the charge of a electron
negative charge -1
what is the relative mass of a proton?
1 m u (atomic mass units)
what is the relative mass of a neutron?
1 m u (atomic mass units)
what is the relative mass of a electron?
1/2000 m u (atomic mass units)
how are the elements in the parodic table arranged?
atomic number / number of protons
how are elements with similar properties place in the periodic table?
they are placed in groups
how did Newlands order his perodic table?
by their atomic weight
what were the ‘groups’ Newlands ordered his table called?
octaves
how did Mendeleev order his periodic table?
by their atomic weight
what are the 2 main differences between Newlands and Mendeleev’s periodic table?
1) M predicted elements that hadn’t been discovered yet and left gaps for these undiscovered elements
2) M altered the strict order of atomic weight so their properties could match
why are the noble gases unreactive?
because they already have full outer shells
why was Mendeleev’s table accepted?
elements he predicted were discovered and their properties matched his predictions
State two key things that Mendeleev did that no one had done before that made his Table work?
- left gaps for elements he believed were yet to be discovered
- changed from weight order for some elements to put them in groups with elements with similar properties
Describe metallic bonding
attraction between nucleus of metal atoms in a lattice to the cloud of delocalised outer shell electrons
Explain why sodium is soft
atoms all the same sizecan slide over each other while maintaining metallic bonding
Explain why bromine has a low boiling point
weak forces between molecules
Sodium reacts with bromine to form sodium bromide. Explain why this reaction takes place in terms of electrons
electrons transferred from sodium atoms to bromine atomsin order for all atoms toget stable electron structures of group 0 atoms
Explain why sodium bromide has a high melting point
strong attraction between positive and negative ions
give 2 similarities in physical properties between group 1 metals and transition metals
*conduct heat
*conduct electricity
*malleable
*ductile
*shiny when polished
give 2 similarities in chemical properties between group 1 metals and transition metals
*react with non-metals to form ionic compounds
*form basic oxides
give 2 differences in chemical properties between group 1 metals and transition metals
*K is (much) more reactive
*Cu forms ions with different charges, K only forms 1+ ions
*Cu forms coloured compounds but K forms white compounds
give 2 differneces in physical properties between group 1 metals and transition metals
*Cu has (much) higher melting point
*Cu has (much) higher density
What method would you use to separate ethanol from a solution of sugar in ethanol
distillation
What method would you use to separate ethanol from a mixture of water and ethanol (they are miscible liquids)
fractional distillation
What method would you use to separate water from a mixture of hexane and water (they are immiscible liquids)
separating funnel
What method would you use to separate iron filings from a mixture of iron filings with water
filtration
what can we separate?
mixtures
what does chromatography separate?
solid from another soluble solid
what does filtration separate?
insoluble solids from a solution
what does distillation separate?
soluble solute from a solution
what does evaporations separate?
soluble solute from a solution
what is the difference between the reason why you sometimes use evaporation to separate and distillation to separate?
sometime you need to collect the solvent itself instead of it just evaporating off
how is simple distillation different to fractional distillation?
SD separates substances with greater difference between boiling points
FD separates substances with boiling points that are closer to each other
Lithium, sodium and potassium are all in group 1 of the periodic table. Which of these has the lowest boiling point?
The melting points of the group 1 metals decrease as you go down the group.
