C1 Flashcards
need to be done: separation methods, group 1,7,0 and scientist and their versions of the periodic table, Rutherford's scattering experiment
\what is an element?
a substance that can’t be broken down into any other substance
- made up of 1 an atom that can bond together
what are compounds?
made up of atoms of 2 or more elements chemically bonded together
- atoms of elements react in chemical reactions to from compounds
how are compounds separated?
by chemical reactions
what is a mixture?
a substance that contains 2 or more different elements or compounds
- NOT chemically bonded
how are mixtures separated?
by physical processes such as filtration distillation
- don’t involve chemical reactions —->
so the elements and compounds don’t change (they are only separated from each other)
what are molecules made of?
one or more atoms that have bonded together
- those atoms can be the same element or different
what is a diatomic molecule?
2 atoms
what is filtration?
method for separating insoluble solid from a liquid
what is crystalisation?
- used to form solid crystals from a solution
- used to separate soluble solid from a liquid
what is simple distillation used for?
used to separate a liquid from a solid
what is fractional distillation used for?
used to separate a mixture of different liquid
- these liquids must have different boiling point
what is chromatography used for?
to separate substances based on their different solubilities
- is used to separate mixtures of more than 1 soluble solvent.
what are all substances made of?
atoms
what is atomic mass?
protons + neutrons
what is atomic number?
protons
what are the 3 subatomic particles
protons, neutron and electrons
what are atoms?
the smallest part of an element that can exist
what is charge and mass of protons?
charge = +1
mass = 1
what is the charge and mass of neutrons?
charge = 0
mass = 1
what is the charge and mass of electrons?
charge = -1
mass = 1/2000
how do you work out the number of electrons?
electrons = number of protons
how do you work out the number of neutrons
atomic mass- atomic number
what are protons neutrons and electrons? where are they found?
they subatomic particles
protons and neutrons found in nucleus
electrons found on energy shells
what does subatomic mean?
inside an atom
what is the equations for Relative atomic mass?
Ar = (% of isotope 1 x mass of isotope 1) + ( % of isotope 2 x mass of isotope 2)
all divided by 100
what are isotopes?
atoms that have the same number of protons but different number of neutrons
what are group 1 elements known as?
alkali metals
what 3 properties of group 1 metals
soft, grey and shiny
what are group 1 metals stored in?
oil because they would reactive with the oxygen in the air rapidly
what happens when group 1 metals are placed in water?
they produce an alkali and hydrogen gas
Are elements more/less reactive as you go down group 1?
more reactive
why are elements more reactive as you go down group 1?
-the outer electron shell is further from the nucleus and more shielded by other shells
-the electrostatic force of attraction between the outer electron and nucleus is weaker
- easier for outer electron to be lost
what ions does group 7 form?
1-
are elements more or less reactive as you go down group 7?
less reactive
why are elements less reactive as you go down group 7?
- there are more electron shells
- the outer shell if further from the nucleus
- the electrostatic forces of attraction between free electron and nucleus is weaker
- harder to attract an electron into the outer shell
what are group 7 elements known as?
Halogens
does the melting and boiling point increase or decrease as you go down group 7?
increase
what do group 7 elements form when they reactive with other non-metal
covalent compounds
what do group 7 elements form when they reactive with metals
ionic compounds
is group 0 reactive or unreactive?
unreactive because they have have a full outer shell so don’t need to lose or gain electrons
what happens to the boiling point as you go down group 0?
boiling point increases
who created the Law of Octaves?
John Newlands
what did John Newland order the periodic table by?
atomic weight
who grouped metals and non-metals together?
John Newland
what did Dimitri Mendeleev order the periodic table by?
atomic weight
what is the modern periodic table ordered by?
atomic number
what consisted of Dimitri Mendeleevs periodic table? 2
-left gaps for undiscovered elements
- predicted properties of undiscovered elements
what did John Dalton discover? when?
At the start of the 19th century atoms were described as solid spheres
who suggested the Plum Pudding model? when?
JJ Thomson in 1897
what did Ernest Rutherford discover? when?
The Alpha scattering experiment
- 1909
-only the nucleus is + charged
-most of the atom is empty space
what did Niels Bohr discover? when?
around 1911- electrons are in shells orbiting the nucleus
what did James Chadwick discover when?
around 1940 - there are neutrons in the nucleus
In what year were electrons discovered? by who?
1897
- J.J Thomson
In what year were protons discovered? by who?
1909
- Ernest Rutherford
in what year were neutrons discovered? by who?
1932
- James Chadwick
