What is the relationship between atomic numbers and atomic radii of elements in group 2a

Naoki's bicycle has a mass of 10 kg. if naoki sits on her bicycle and starts pedaling with a force of 168 n, causing an acceleration of 2.8 m/s2, what is naoki's mass?

Electrons are extremely important to what area of technology? a) anti-aging research b) household product development c) electronics d) drug discovery

Compare and contrast the bohr model and the electron cloud models of the atom.