C3 Flashcards
Properties of the alkali metal group 1 ?
Low mp
The melting and boiling point decreases as we go down the group
Why does the alkali metal become more reactive as it goes down the group ?
The elements becomes more reactive down the group because it becomes easer for them to lose their outermost electrons this is due to the atom increasing in size found down the group
Why is the alkali metals stored under oil ?
Because they react very vigorously with oxygen and with water
Properties of group7 the halogens?
The mp and bp increases as you go down the group
Less reactive as you go down the group
Poor conductor of heat and electricity
Why is the elements less reactive as you go down group 7 ?
Because it becomes harder for them to gain an electron . This is due to the atoms increasing in size going down the group
In the early 1800s Wattwood are too obvious way to categorise elements ?
Their physical and chemical properties
Their relative atomic mass
What were New Zealand’s law of octaves ?
You noticed that every eighth element had similar properties and so he listed some of the known elements and roles of seven
Why was. Newlands law on octaves criticised?
This was because his groups contained elements that didn’t have similar properties e.g. carbon and Titanium
He mixed up metals and nonmetals e.g. oxygen and iron
He didn’t leave any gaps for elements that hadn’t yet been discovered
What did Mendeleev do differently to Newlands ?
Mendeleyev put the elements in order of atomic mass like a new learns that he had to leave gaps in order to keep elements with similar properties in the same vertical column known as groups
He was prepared to leave some very big gaps in the first two rolls before the transition metals come in on the third rows
The gap that Mendeleev had left was really Clever because…
They predicted the properties of undiscovered elements and when they were phone they fitted the pattern
What are properties of transition elements ?
They are good conductors of heat and electricity
they are very dense strong and shiny
Transition metals are much less reactive than group for metals and they don’t react vigourously with water or Oxygen
They have a higher melting point how much denser and stronger and Harder then group 1 Metals
What are the two types of water?
There is hard water and there is Softwater
What are the two affects of hard water
Hard water makes scum and scale
What causes hard water?
Hard water is caused by calcium and magnesium ions
What are the advantages of hard water?
Calcium irons are good for healthy teeth and bones
Studies have found that people who live in hard water areas on at less risk of developing heart disease and people who live in soft water areas
What are the two types of hard water?
Temporary hardness And Permanently hardness
What is temporary hardness caused by
Is caused by the hydrocarbonate Ions HCO3
What is permanent hardness caused by?
Is caused by the dissolved calcium sulphate
What are the advantages of hard water?
Calcium irons are good for teeth and bones
Study has shown that hard water is good for your heart
Some people prefer the taste of hard water
What are the disadvantages of hard water ?
Hard water poured with Tom which is where calcium and magnesium irons are presented in the water
you need more soap this is because calcium and magnesium reacts with the soap so does not foaming as you would like
Lime scale
What are different ways to treat hard water?
Washing soda- sodium carbonate
This reacts of the calcium ion in the hard water to make insoluble participate of the calcium ions and magnesium ions
the sodium ion Are left in the water
Ion exchange Column
Sodium ions can be exchanged for calcium or magnesium ion in the water that runs
what is a disadvantage of using a ion exchange column?
Columns need replenishing with more sodium ions after a while
What are the method to used in a water treatment plant?
The water passes through mashed screen to remove the bits like twigs
chemicals are added to make solids and micro stick together and fall to the bottom
water is filtered through a gravel bed to remove all the solid
Water is then chlorinated to kill off any harmful microbes left.
What are some advantages to add fluoride into water
It’s good for your teeth and bones and for people who have poor dental hygiene
Only a small amount of fluorine is been added to the water
There is no evidence that there is any harm for a fit of flooring been in the water apart from fluorosis
What are the disadvantages of adding fluoride into water?
Studies have shown exes fluoride can affect the brain
Although with a small amount you can’t set limits as you can’t control people intake of the water
It is ethnically wrong to give people treatment they have not consented to
Water is a natural resource describe the process involved in the water cycle?
Evaporation
Condensation
precipitation
Surface run-off
Define an exothermic reaction?
An exothermic reaction is one which gives out energy to the surrounding usually in the form of heat and usually shown by a rise in temperature
