What do we mean when we say that a nucleus undergoes radioactive decay?

Which compound is held together by the electrostatic force between two ions? a. co2 b. cci4 c. h2s d. mgf2

Identify the correct relation showing that the radius r of the orbit of a moon of a given planet can be determined from the radius r of the planet, the acceleration of gravity at the surface of the planet, and the time τ required by the moon to complete one full revolution about the planet. determine the acceleration of gravity at the surface of the planet jupiter knowing that r = 71 492 km and that t= 3.551 days and r= 670.9 × 10^3 km for its moon europa.

Eof 20 degrees. the index of refraction of air is 1.0003, and the index of refraction of water is 1.33. the angle of refraction rounded to the nearest whole number is °.