Topic 1 - atomic structure and periodic table Flashcards
(19 cards)
1
Q
How does distillation work?
A
- simple distillation used for separating a liquid from a solution
- solution is heated - part of solution that has lowest boiling point evaporates first
- in the condenser, the vapour is cooled + condensed - collected
- rest of solution is left behind in flask
2
Q
How does fractional distillation work?
A
- fractional distillation used to separate miscible liquids
- put mixture in flask and puting fractionating column on top -then heat it
- different liquids hvae different boiling points - evaporate at diferent temperatures
- liquid with lowest boiling point evaporates frist - when temperature of thermometer reaches boiling point of liquid - reach top of column
- liquids with higher boiling points may also start to evaporate - column is cooler toward the top - condense + run back down to flask
3
Q
What was the plum pudding model?
A
- in 1897 JJ Thompson conlucded from experiments that atoms weren’t solid spheres
- his measurement of charge and mass showed that atom must contain small negatively charged particles - electrons
- showed the atom as ball of positive charge with electrons embedded in it
4
Q
What was the nuclear model?
A
- 1909 ernest rutherford fired positively charged alpha particles through thin sheet of gold
- most particles went straight through like expected - some deflected more than expected - some deflected backwards
- tiny positively charged nucleus at centre -mass concentrated - cloud of negative electrons surround it
5
Q
What was Bohrs model?
A
- niels bohr suggest all electrons were contained in shells
- proposed that electrons orbit nucleus in fixed shells - each shell fixed difference from nucleus
6
Q
How did elements use to be arranged?
A
order of atomic weight
7
Q
What was Dmitri Mendeleev’s table?
A
- he arranged elements mainly in atomic mass - also considered chemical properties and made adjustments to the order for elements with similar properties to align them in groups
- he left gaps for undiscovered elements - he could predict their properties
- when these elements were discovered and matched his predictions - proved validity of his arrangement
8
Q
Propertries of metals?
A
- all have metallic bonding
- strong and malleable
- good heat and electricity conductors
- high melting and boiling points
9
Q
Properties of transition metals?
A
- very dense, strong, shiny
- form ions with different charges/more than one ion
- form coloured compounds
- make good catalysts
10
Q
Peroperties of group 1 elements?
A
- very reactive
- soft and low density
- increasing reactivity down group
- lower melting/boiling points down group
- higher relative atomic mass down group
11
Q
Alkali metal reactions with water?
A
- react vigorously
- produce hydrogen gas + metal hydroxides (compound that dissolves in water to produce alkaline solutions)
12
Q
Alkali metal reactions with chlorine?
A
- react vigorously
- form white metal chloride salts
13
Q
Alkali metal reactions with oxygen?
A
- form metal oxides
- this is why group 1 metals tarnish in air - react to form dull metal oxide layer
14
Q
Physical differences in properties between alkali metals and group 1 metals?
A
- transition metals higher melting and boiling points
- transition metals higher density
- transition metals harder
15
Q
Chemical differences in properties between alkali metals and group 1 metals?
A
- group 1 much more reactive than transition metals
- group 1 metals always form ions with +1 charge, transition metals form ions with different charges
- group 1 metals form white/colourless compounds, transition metals form colourless compounds
16
Q
What are the halogens?
A
- Florurine - very reactive - poisonous yellow gas
- Chlorine - farily reactive - poisonous dense green gas-
- Bromine - dense - poisonous red-brow volatile liquid
- Iodine - dark grey crystalline solid - purple vapour
17
Q
Halogen trends?
A
- less reactive down the group
- higher melting/boiling point down group
- higher relative atomic mass down group
18
Q
What are group 0 elements?
A
- noble gases - inert, colourless gases
- all have full outer shells
- as outer shell is stable - dont need to gain or give up electrons to become more stable
- means they dont react much at all
- exist as monatomic gases
- all colourless gases at room temp
19
Q
Trends of noble gases?
A
- boiling points increase moving down group
- atomic mass increases down group
- increase in boiling point due to increase in number of electrons in each atom - greater intermolecular forces
