PERIODIC TABLE Flashcards
(29 cards)
First ionisation energy
Energy required to remove one mole off electrons from each atom in the gaseous state
Factors affecting ionisation energy
- Atomic radius- greater the distance between the nucleus the lower the nuclear attraction .
2.. Electron shielding-electrons are negatively charged so inner shell electrons repel outer shell electrons - Nuclear charge-more protons the greater the attraction
Ionisation energy decreases as we go
Down a group as the atomic radius increases and the electron shielding increases weakening attractive forces
Ionisation energy decreases as we go
Across a period . Due to a increase in nuclear charge as the number of protons increases meaning an increase in nuclear charge . And shielding is also vey similar across a period .
Most group 2 elements are
Reducing agents
Group 2 elements re labelled as reducing agents because
As they reduce other species
When magnesium reacts with oxygen
Magnesium burns with a white light
When group 2 elements react with water
Reaction is more vigorous as we go down the group
When group 2 element react with water (OH)
Alkaline hydroxide
Reactivity increase we go down the group due to
-as we are losing 2 electrons forming 2+ ions
-it is requiring energy fro the 1st and 2nd ionisation energies
Group. Oxides are
Only slightly soluble in water and forms a solid precipitate when saturated
uses of group 2 elements; Agriculture
Calcium hydroxide is added to fields by farmers to increase the Ph of acidic soils as it neutralises the soils
Uses of group 2 elements: Medicines
Group 2 bases can be used as antacids for treating acid indigestions . Such as milk of magnesia
Group 7 elements at room temperature and pressure are
Diatomic molecules
Group 7 elements can be found in
Dissolved seawater
Fluorine
Pale yellow gas
Chlorine
Pale green gas
Bromine
Red brown liquid
Iodine
Shiny grey solid
Astatine
NEVER BEEN SEEN BEFO
Trends in boiling point: Group 7
More electrons , more London forces more energy needed to break these London forces as we go down the group
Trends in group 7 elements;Reactivity
Atomic radius increases more inner shells so outer electrons repel inner electrons less nuclear attraction
The halogens are commonly
Oxidising agents
Each halogen has seven outer shell electrons and the
S sub shells have 5 electrons . 2s2 3p5
