Topic 4-Inorganic Chemistry And The Periodic Table Flashcards
What is the test for ammonium compounds?
Gas turns damp red litmus paper blue.
Name the 2 problems with the flame test
Sodium compounds (as impurities) can mask other colours
Subjective —> people have different levels of vision so a word description maybe mean different colours to different people.
What causes the colours in the flame tests?
Electrons can absorb energy and move to higher energy levels.
Instantly returns to ground state which releases energy and sometimes this energy is within the radiation of the visible light spectrum which makes a colour appear.
Define electronegativity.
The ability of an atom to draw a pair of bonding electrons from a covalent bond.
Describe the trends of reactions of group 7 with chlorine.
More vigorous down the group.
Describe the trend in reactions of group 7 with oxygen
More vigorous down the group
How do group 2 elements generally react with water?
What is an exception?
M + H2O —> M(OH)2 + H2
metal + water –>metal hydroxide + hydrogen
Magnesium and steam (reacts slowly) is an exception as it forms Magnesium Oxide and hydrogen
What group 2 oxide doesn’t react with water?
Beryllium
What could Mg(OH)2 be used for and why?
Indigestion tablets as Magnesium Hydroxide is very insoluble so won’t react/dissolve into the body.
What is BaSO4 used for and why?
Barium meal for patients about to have an x-ray as it absorbs the x-rays so can be traced but is insoluble so the toxicity won’t affect the body.
What is the interaction between the nucleus and outer electrons called?
Electrostatic attraction
How does group 2 react with oxygen?
Group 2 metals will BURN in oxygen to form solid white oxides.
How does group 2 react with chlorine?
Group 2 metals form white chlorides when reacting with chlorine.
The oxides form more strongly alkaline solutions a you go ….. the group?
Down the group
Oxides and hydroxides are examples of what?
Bases.
What makes metal hydroxides in solutions strongly alkaline?
The hydroxide ions (OH-).
What will bases do to dilute acids?
Neutralise them.
Name the flame colour of Li, Na,K,Rb,Cs (Group1 )
Li=red Na=yellow K=lilac Rb=red Cs=blue
Name the flame colour of Ca,Sr,and Ba (Group 2)
What are the colours of the other Group 2 elements?
Ca=brick red Sr=crimson Ba=Green No colour (radiation beyond the visible light spectrum)
Name the risks of adding Chlorine to water?
Chlorine gas is toxic
Liquid chlorine burns the eyes and skin
What does adding to water and Chlorine do? (in absence of sunlight)
Cl2 + H2O –> HCl + HClO
which ionises to make CLO- which kills bacteria to clean water!
Name some benefits of water treatment
Kills harmful bacteria
prevents deaths
What do Group 1 carbonates decompose to?
They don’t decompose (thermally stable)
What do Group 2 carbonates decompose to?
Oxides and carbon dioxide.
What do Group 2 Nitrates decompose to?
Oxygen, oxide, nitrogen dioxide
What do group 1 Nitrates decompose to?
Nitrite, oxygen.
Halogens undergo what kind of reaction with COLD ALKALIS?
Disproportionation
Halogens + hot alklais undergo a ……… reaction
disproportionation
Define the general trend of reactivity of Group 7
Less reactive down the group
What trend do melting and boiling points have down Group 7?
Increase down the group
Which species is displaced: halogens/halides
Halogens displace less reactive halides e.g. Cl2 displaces Br- and I-