CC4- Periodic Table

Question 1

Elements and The Periodic Table

Answer 1

• Created by Mendeleev. Left gaps in his table for new elements to be found
• Sometimes swapped positions if chemical properties suited better.
• Eg, Put iodine after Tellerium even though it was lower atomic mass, so it lined up with elements of similar chemical properties(with fluorine,Chlorine)
• Used gaps in table to make predictions about properties of unfound elements

Question 2

Atomic Number and Periodic Table

Answer 2

-In 19th century group of unreactive metals were found and put into Group 0
-Moseley realised atomic number must be amount of protons in nucleus.
-Elements in a row(Period) are in order of increasing Atomic number
Elements in Same column(group) have similar properties

Question 3

Electronic Configurations and Periodic Table

Answer 3

• Electrons fill shells in an atom, like filling bus one seat at a time from front.
• Number of electrons in outer shell is equal to the group number, apart from group 0 as they have full outer shells.
• Number of occupied shells is equal to period number