Periodic Table Flashcards
What was wrong with Newlands periodic table?
His groups contained elements which didn’t have similar properties (carbon and titanium)
He mixed up metals and non-metals (oxygen and iron)
He didn’t leave any gaps for elements that hadn’t been discovered.
How did Mendeleev arrange the periodic table?
Arranged the elements in order of atomic mass.
Left gaps in order to keep the elements with the same properties in the same vertical columns.
What was good about Mendeleev’s periodic table?
He left gaps so you were able to predict the atomic masses and properties of undiscovered elements.
What evidence is there in favour of the periodic table?
After Mendeleev released his periodic table, newly discovered elements fitted into the gaps.
After the discovery of the atomic structure scientists realised it matches up well and is a useful summary of the structure of the atom.
What does each group number stand for?
The number of electrons in the outer shell of each element in the column.
How are the elements in the periodic table arranged?
By their electronic structure.
What happens when an atom has more outer shells?
The attraction from the nucleus is less as there are more inner electrons, meaning more screening/shielding.
This means an electron is more easily lost because there’s less attraction from the nucleus holding it in place.
Also it is less likely to gain an electron as there’s less attraction pulling electrons into the atom.
What are the group 1 elements called?
The alkali metals.
What are the properties of the group 1 elements?
Low density.
Form ionic compounds with non-metals to form 1+ ions.
React with water, releasing hydrogen.
What happens as you go down the group 1 elements?
As you go down the alkali metals:
Become more reactive.
Have lower melting and boiling points.
What are the alkali metals?
Lithium Sodium Potassium Rubidium Caesium
What compounds do alkali metals produce?
They produce white compounds that dissolve in water to form colourless solutions.
What do group 1 elements produce when reacting with water?
Hydrogen gas and they form hydroxides that dissolve in water to give alkaline solutions.
What are the properties of transition elements? (compared with group 1 metals)
Have much higher melting and boiling points.
Are harder and stronger.
Are much less reactive and so don’t react as much with water and oxygen.
Also good conductors of heat and electricity.
What properties of transition elements make them good building materials?
Thy are dense and strong.
Don’t react as much with water an oxygen.
