How many neutrons does element X have if its atomic number is 21 and its mass number is 95?

Which radioisotope is used in dating geological formations? (1) I-131 (2) U-238 (3) Ca-37 (4) Fr-220

The atomic number of oxygen is 8, because oxygen has a. electrons in eight shells. b. an atomic mass of 8. c. a second shell with eight electrons. d. eight protons in the nucleus

A change in temperature causes a change in mass. True False

How does the distance between the planet Earth and the Sun compare with the distances between the planet Earth and other stars? A. About half of the other stars are closer to Earth than the Sun. B.

What takes place when you inhale and exhale

A solution consists of a solute and a solvent mixed together. for the solution in model 1 identify and provide the symbol for the a. solute. b. solvent.

What is meant by a " chain reaction "?

Describe the direction of the wind movement around the center of high air pressure

How much volume (in cm^3) is gained by a person who gains 11.5 lbs of pure fat?

A compound contains 69.94 percent iron and 30.06 percent oxygen. what is its molecular formula if the molar mass of the compound is 199.55 grams per mole?