facts Flashcards
how to Mendeleev order elements
by atomic mass
why did Mendeleev leave gaps in his periodic table?
left gaps for undiscovered elements
how is the modern periodic table organised?
-by atomic (proton) number and arranged into groups and periods
what is the number of occupied shells the same as
the period number
what is the number of outer shell electrons the same as
the group numbers
what are the horizontal rows in the periodic table called
periods
what side are metals on (periodic table)
left (blue)
what side are non metals on
right (green)
whats placed in the same vertical groups
elements with similar properties
how is acid rain produced
sulfur dioxide and oxides of nitrogen dissolve into war in the air to produce acid rain
non renewable fuels examples
crude oil
natural gas
what is being explored as an alternative fuel for cars
hydrogen
an environmental problem caused by acid rain
the rain makes rivers more acidic,harming the organisms living in them
hydrogen advantages
-it burns easily
-it doesn’t produce ash or smoke
-it only produces water when it burns
-it releases nearly three times as much energy per kg as petrol
hydrogen disadvantages
-it is a gas,so it has to be stored at high pressure
-filling stations would need to be adapted for hydrogen to be used in cars
what did the early atmosphere mostly consit of?
carbon dioxide
what did photosynthesising life forms produce over time
oxygen
what does today’s atmosphere consist of?
78% nitrogen and 21% oxygen
what formed the earths early atmosphere
gases produced by volcanic activity
How were the early oceans formed?
water vapour in the atmosphere condensed and fell as rain
how to test for oxygen
A glowing wooden splint relights in the presence of oxygen
how to test for hydrogen
a lighted wooden splint ignites hydrogen with a ‘pop’
test for carbon dioxide
limewater turns milky in the presence of carbon dioxide
what does complete combustion produce
carbon dioxide and water
