SC3b - Atomic Number And Mass Number Flashcards
What lead Rutherford to conclude atoms are mostly empty space with a small positive central nucleus that has most of the mass?
By firing positive particles at a thin gold foil and noticing most particles passed straight through the foil with very few being deflected or bouncing back
How is the periodic table ordered?
With the amount of protons in the nucleus, the atomic number
How is an element defined?
By its atomic number
How were elements in the periodic table originally placed?
Order of the masses of the atoms
Why was the original periodic table order changed?
Elements ended up being grouped with others that has very different properties
What does it mean that the mass of an electron is negligible?
It’s so small it can be ignored
Why does the nucleus of an atom contain most of the mass?
As it doesn’t have any electrons and is only made of protons and neutrons and electrons have a tiny amount that’s negligible
