The Periodic Table Flashcards
Who attempted to classify elements by arranging them in order of their atomic weights?
Newlands and then Mendeleev.
Why is the periodic table called a periodic table?
Because similar properties occur at regular intervals.
In the early periodic table how are elements arranged?
Elements with similar properties are in columns, known as groups.
Why was the early periodic table not very good?
It was incomplete and some elements were placed in inappropriate groups, if the strict order of atomic weights was followed.
How did Mendeleev overcome some of the problems?
He left gaps for elements that had not yet been discovered.
When were electrons, protons and neutrons discovered?
Early in the 20th Century.
When did the periodic table become arranged in order of atomic numbers?
When electrons, protons and neutrons were discovered early in the 20th century.
Elements in the same group have the same number of _________ in their highest occupied energy level.
Electrons.
What are the properties of elements in group 1?
Metals with low density, react with non-metals to from ionic compounds which carries the charge or 1+- the compounds are white solids that dissolve in water to form colourless solutions, react with water releasing hydrogen, form hydroxides that dissolve in water to give alkaline solutions.
The further down an element is in group 1…
The more reactive the element
The lower its melting point and boiling point.
Differences between alkali metals and transition metals.
Transition metals have higher melting points (except for mercury) and higher densities,
Transition metals are stronger and harder,
Transition metals are much less reactive and so do not react as vigorously with water or oxygen.
What are the properties of transition metals?
Have ions with different charges, form coloured compounds and are useful catalysts.
Which group of elements react with metals to form ionic compounds where the halide ion carries a charge of 1-?
Halogens.
The further down an element in group 7 is..
The less reactive the element,
The higher its melting point.
A more reactive halogen can displace a ____ ________ _______ from an aqueous solution of its salt.
Less reactive halogen.
