P1.1

• describe how and why the atomic model has changed over time

  Because scientists are constantly finding new information about atoms so they change it to make the model reliable.
• describe structure of atoms and charges , relative size of particles

  Nucleas in the middle ( containing moss of its mass) with protons and nuetrons - has positive charge . Orbiting it is electron shells - neutral charge
• Typical size of atoms and small molecules

  atoms -1 ×10-10 m small molecules -10-10m
• Density

  How much space object takes up in relation to its mass
• explain differences in density in states of matter

  Solid -high density ,liquid - less dense , gas- low density
• Apply relation between density , mass and volume to changes where mass is conserved

  Shape can change but mass is conserved -mass remains constant , density and volume also remains constant