Periodic Table Flashcards
Compare mendeleev’s periodic table with the modern periodic table
mandeleev’s table-modern table
- less elements-more elements
- gaps left for undiscovered elements-no gaps
- in order of atomic weight -order of atomic number
Define the term element?
it is a substance that cannot be split into simpler substances by chemical means
What is the periodic table?
a table of the chemical elements arranged in order of increasing atomic number
Distinguish between elements and compounds
An element is something that cant be divided into simpler substances while compounds can be divided
State the principle resemblances of elements within each main group, in particular alkali metals, alkaline earth metals, halogens and noble gases
Group 1 and 2 are highly reactive while group 7 to 8 are inert and unreactive
Describe the reaction between water and lithium,sodium, and potassium having seen the reaction demonstrated
The water bubbled,fizzed, lit up and dissolved
describe by means of the chemical equation the reaction between water and lithium, haven seen the reaction demonstrated
2Li + 2H20 = 2Li0H + H2
Lithium + Water = Lithium Hydroxide + Hydrogen
describe by means of the chemical equation the reaction between water and sodium haven seen the reaction demonstrated
2Na + 2H20 = 2Na0H + H2
Sodium + Water = Sodium Hydroxide + Hydrogen
describe by means of the chemical equation the reaction between water and potassium haven seen the reaction demonstrated
2K + 2H2O = 2K0H +H2
Potassium + Water = Potassium Hydroxide + Hydrogen
Outline the history of the idea of elements, including the contributions of Greeks
Elements are the basic things of which all others are made
The elements are earth,fire,air and water
Outline the history of the idea of elements, including the contributions of Boyle
Known as the father of chemistry
proposed that elements are substances are that cannot be divided into smaller substances
Outline the history of the idea of elements, including the contributions of Davy
discovered many elements by electrolysis of salts. Ex-potassium and salts
electrolyzed water to find it was made up of hydrogen and oxygen in a 2:1 Ratio
Outline the history of the idea of elements, including the contributions of Moseley
used X-rays to discover the number of protons in each element. i.e atomic number
he found that the elements in the periodic table are in order of atomic number
outline the contributions of Mendeleev to the structure of the modern periodic table
Arranged elements in order of atomic weight
there were periodic trends in properties
Why did mandeleevs periodic table stick while others didn’t
he left gaps for missing elements
reversed Te and I
put elements into subsets
