Until recently, the elements were arranged in order of their [blank_start]atomic mass[blank_end].
Answer
atomic mass
atomic number
names (alphabetically)
Question 2
Question
What were the problems with Newlands' Law of Octaves?
Answer
The groups contains elements that didn't have similar properties e.g. C and Ti
He mixed up metals and non-metals e.g. O and Fe
He didn't leave any gaps for undiscovered elements
They weren't arranged in order of atomic mass
They went against the Church
Question 3
Question
Group 1 metals become [blank_start]more[blank_end] reactive as you go down the group because the outer electron is more easily lost as it's further from the nucleus.