topic 2 Flashcards
why are group 2 compounds less thermally stable than group 1?
the greater the charge of the cation, the greater the distortion and the less stable the carbonate/nitrate compound becomes
group 1 carbonates decomposition
they are thermally stable it can’t be heated by a bunsen but with a higher temp it can
except Li2CO3 - Li2O + CO2
group 1 nitrates decomposition
decompose to form a nitrite and oxygen
2KNO3 - 2KNO2 + O2
group 2 carbonates decomposition
oxide and carbon dioxide
CaCO3 - CaO + CO2
flame test colours
Na
K
Li
Rb
Cs
Sr
Ba
Na-orange/yellow
K-lilac
Li-red
Rb-red
Cs-blue
Ca-brick red
Sr-crimson
Ba-green
how do you do a flame test
1)add HCL to nichrome wire
2)heat nichrome wire in a hot bunsen flame to clean it
3)dip the nichrome wire to the compound and hold it to a flame
what are bases?
oxides and hydroxides
group 2 hydroxide solubility rule
as you go down, the solubility increases
group 2 sulfates solubility rule
as you go down the solubility decreases
fluorine:
1)colour
2)physical state at room temperature
1) pale yellow
2)gas
chlorine
1)colour
2)physical state at room temperature
1)green
2)gas
fluorine
1)colour
2)physical state at room temperature
1)red brown
2)liquid
iodine
1)colour
2)physical state at room temperature
1)grey
2)solid
why do halogens (group 7) get less reactive down the group
atom becomes larger so outer electrons are further from the nucleus.
outer electron is shielded more from the attraction of the positive nucleus because they’re more inner electrons
melting point increases down group 7 because
greater net london force, and the increase in london force makes it harder to overcome the intermolecular forces, and so melting point and boiling point increases
