In the Bohr model, what holds the electron in orbit? Select one:
a. a gravitational force
b. the energy of the sun
c. the attraction of the positive proton and negative electron
d. the track that is laid out around the nucleus

Express the following number in scientific notation. 0.026890 =

Which sentence about particles in matter is true? a. atoms are present in solids and liquids but not in gases. b. the particles of matter are in constant motion. c. the same kinds of atoms are found in different elements. d. when a solid changes to a liquid, the sizes of the particles change.

Ascientist is measuring the pressure that is exerted by each of the following gases in the atmosphere: carbon dioxide, oxygen, and nitrogen. which term most likely describes what she is measuring?