The Atom Flashcards
What is the mass number
Top number that is the sum of protons and neutrons
What is the atomic number
Number of protons and electrons
Why did Mendeleev reverse the order of elements?
So elements were in groups with similar properties
What is the modern name for atomic weight?
Relative atomic mass
Why did Mendeleev’s periodic table become more widely accepted than previous versions?
Mendeleev predicted properties of missing elements
Elements were discovered to fill the gaps
Properties matched his predictions
Describe what you would see when sodium reacts with chlorine
Flame
White solid forms
Chlorine fades away
Describe 3 differences between the nuclear model and plum pudding model
Nuclear model is mostly empty space whereas ppm is a ball of positive charge
Nuclear model electrons and nucleus are separate whereas ppm electrons embedded
Nuclear model has mass concentrated at nucleus
Describe the change that Bohr made to nuclear model
Electrons orbit the nucleus at specific distances
Why are most alpha particles not deflected?
Atom is mainly empty space
What are group 7 known as?
Halogens
State the two conclusions drawn from Rutherford’s alpha-scattering experiment.
The mass of atom concentrated at nucleus
Nucleus is positive charged
