C2.1, 2.2 And C3.2 Flashcards
Periodic table
The table arrangement of the elements, they are ordered by their atomic number (number of protons) and chemical property similarities
How many elements in the periodic table
118
What are groups in the periodic table
Groups are the vertical collumns that show the elements in that specific group: React similarly, have similar chemical properties and have a similar structure. They all have the same number of electrons on their outermost shell
What are periods in the table
Periods ars the horizontal rows with all the elements in that period having the same number of atomic shells
John Dalton (start of 19th century) discovery
Made ‘solid sphere model’ adapted greek idea of atoms and stated that they are indivisible, he defined that compunds were made up of different types of atoms and that those of a given element were identical
JJ Thomson 1897
‘Plum Pudding model’- He discovered electrons (which he nicknamed corpuscles) in atoms and showed them scattered with a positive charge
Ernest Rutherford (around 1909)
‘Nuclear model’- Discovered the nucleus by firing positively charged atoms at it and saw that they repelled from the protons inside of it
Niels Bohr (around 1913)
‘Planetary model’- Said that electrons orbitted the nucleus in shells of fixed sizes and energies
James chadwick (around 1940)
‘Quantum atomic model’- Discovered the neutron in the nucleus
Mendeleev (1869)
Made a table for the elements in order of atomic weight, he left space for missing elements and predicted the characteristics so he could make as much of the table as possible
Newlands 1864
‘Law of Octaves’ - noticed that the properties of every eighth element was similar but didn’ take into account missing elements so his theory was shut down as it stopped working at around carbon
