C2-The Periodic Table Flashcards
How was John Dalton’s periodic table arranged?
In order of atomic weight
How was John Newland’s periodic table arranged?
In order of mass and in octaves as the properties of every eighth element seemed similar
Why was John Newland’s periodic table not accepted?
He assumed that all the elements had been found and did not take into account that chemists were still discovering new ones. So he filled in his octaves even though some of the elements were not similar.
How was Mendeleev’s periodic table arranged?
In order of atomic weight and in a regular occuring pattern of properties, with gaps for elements that had not yet been discovered
Why was Mendeleev’s periodic table approved years later?
He left gaps for elements which had not yet been discovered and used the table to predict what their properties should be
How are elements arranged in today’s periodic table?
In order of atomic (proton) number
Why do elements in the same group react in a similar way?
They all have the same number of electrons in their outermost shell
What is the name for group 1 elements?
Alkali metals
How does the reactivity of group 1 metals change going down the group?
It increases
Properties of the alkali metals
Very low densities, soft and shiny
How do the melting and boiling points of group 1 metals change going down the group?
They decrease
Reaction of alkali metals with water
Metal + water ——–> metal hydroxide + hydrogen
Why is there fizzing when you add lithium, sodium or potassium to water?
The metal reacts with the water to form hydrogen gas
Why is there a flame when potassium reacts with water?
It reacts so vigorously that the hydrogen produced ignites
Properties of the ionic compounds formed when alkali metals react with non-metals
They are white and dissolve easily in water. The solutions formed are colourless
