1.6 - The Periodic Table Flashcards
What pattern is there for melting points in group 1?
The melting point decreases down group 1.
Whats the pattern of melting points across the periodic table?
Melting points of elements increase up until group 4 and then decrease down to group 7.
What is the pattern for melting point in group 7?
Melting points decrease up group 7.
What pattern is there for ionisation energy and electronegativity in groups and periods?
Increases across a period and up a group.
What type of elements (REDOX) are S-block?
They are reducing, they accept electrons and form cations easily.
What type of elements (REDOX) are P-block?
They are oxidising (group 6 and 7 give off electrons and form anions easily)
Are the oxides of S-block acidic or basic?
Acidic
Are the oxides of P-block acidic or basic?
Basic
How is the periodic table arranged?
Elements are arranged by increasing atomic number
8 vertical groups and 7 horizontal periods
Outer electron number corresponds to the group
What is meant by ‘redox’?
Reduction is gain of electrons
Oxidation is loss of electrons
What is an oxidising agent?
Species that accepts electrons, thereby helping oxidation. It becomes reduced itself in the process.
What is a reducing agent?
Species that donates electrons, thereby helping reduction. It becomes oxidised itself in the process.
What can oxidation numbers help do?
Helps work out what has been oxidised or reduced in a redox reaction.
What are the 6 rules for oxidation numbers?
- All elements have an ON of 0
- Hydrogen is 1, unless with group 1 metal (then is -1)
- Oxygen is -2, unless its a peroxide or reacted with fluorine, then its also -1
- Group 1 and 2 elements are 1 and 2 respectively
- Group 6 and 7 elements are -2 and -1 respectively
- ON in a compound must add up to 0 or the ions charge
What are 3 similarities of reaction between group 1 and 2?
- both groups form oxides with oxygen or air
- both groups form hydroxides with water
- oxides/hydroxides are basic and react with acids to form a salt and water
What is the trend in reactivity in group 1 and 2?
Increasing reactivity down both groups.
What is the flame test for Li?
Red
What is the flame test for Na?
Orange/yellow
What is the flame test for K?
Lilac
What is the flame test for Rb?
Reddish violet
What is the flame test for Cs?
Blue violet
What is the flame test for Ca?
Brick red
What is the flame test for Sr?
Red
What is the flame test for Ba?
Apple green
What is the solubility like in S-block elements?
All g1 salts are soluable in water
Solubility of g2 varies with what compound it has merged with
What is important about calcium carbonate?
Important in the structure of rocks
What is important about calcium phosphate?
Its a component of bone tissue
Where are magnesium and calcium ions essential?
Biochem reactions in living organisms
Which group is the most electronegative?
Group 7, they react to form anions with an oxidation state of -1
What is the trend in reactivity in the halogens and why?
Reactivity reduces going down the group, as they are less able to attract electrons due to the size of the atom (less effect from the positive nucleus on the valence shell)
What is the trend in melting points in the halogens and why?
Increase down the group as the intermolecular forces become stronger as the atom gets bigger
What coloured precipitate do you get if you mix silver nitrate and chloride?
White (and also is the only one to dissolve in an aq ammonia solution)
What coloured precipitate do you get if you mix silver nitrate and bromide?
Cream
What colour precipitate do you get if you mix silver nitrate and iodide?
Yellow
Why is chlorine added to drinking water?
To kill dangerous bacteria and viruses such as cholera and typhoid, thereby preventing the outbreak of serious disease.
What is fluoride thought to help?
It is said to reduce tooth decay in children by strengthening tooth enamel and preventing cavity formation.
