PERIODIC TABLE Flashcards
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
