c1 - atomic structure and the periodic table Flashcards
size of atom
1x10 -10m
radius of a nucleus
1 x 10 -14m
why do atoms have no overall charge
the relative charge for an electron is -
and proton is +
number of electrons = number of protons
what is mass number
total number of neutrons and protons
avogados constant
6.02 x 10^23
what is atomic number
number of protons
electron shell limits
2,8,8,2
what is an isotope
Atoms of the same element can have different numbers of neutrons
abundance equ
(isotopic mass number x abundance) + (isotopic mass number x abundance) divided by 100
jj thomson plum pudding model
A ball of positive charge with electrons embedded inside.
how did rutherford prove the plum pudding model was wrong
Alpha particle scattering experiment.
Fired positive alpha particles at gold foil.
Most particles passed straight through = mainly empty space.
Only a few were deflected back = small positively charged centre where mass is
what did bohr do to the nuclear model
electrons orbit the nucleus
at specific distances from the nucleus
what is an element
made of only 1 type of atom. Found in the periodic table
what is a compound
2 or more elements chemically joined together in a fixed ratio.
what is a mixture
2 or more elements or compounds, not chemically joined.
How would you extract salt from a sand and salt solution?
Filter to remove the sand.
Evaporate to remove the water.
Separating mixtures
Filtration
Chromatography
Distillation
newlands development of the periodic table
Ordered by atomic weight
Elements were therefore in wrong groups
Metals were in groups with non metals
mendeleev development of the periodic table
Ordered in atomic weight but changed it so elements are in groups with similar properties
Left gaps for undiscovered elements
When elements were discovered, they had properties which matched Mendeleev’s predictions
why did mendeleevs periodic table become more widely accepted
predicted properties of missing elements
elements were discovered
they matched his predictions
properties of alkali metals
Soft
Low density
Low melting and boiling points
Very reactive
Form white compounds
alkali metals reactions with water
produce hydrogen and a metal hydroxide solution.
alkali metals reactions with oxygen
oxides
alkali metals reactions with chlorine
chlorides
group halogens
less reactive as you go down
less volality
less solubility
melting and boiling decrease
Group 7 Halogens reactions:
The chlorine displaces the bromide as it is more reactive than bromine
why is there a higher boiling point
relative formula mass increases
so intermolecular forces increase in strength
more energy is needed to overcome
why do elements in the same group react in a similar way
same number of electrons in the outer shell
group 0 chemical properties
Inert (unreactive due to full outer shell).
Non-flammable
Colourless gases at room temperature.
Boiling point increases
properties of transition metals
Form ions with different charges
Different coloured compounds
Used as catalysts
Unreactive
Strong
High density
High melting points
Hard
Good conductors of electricity
Good thermal conductors
