Which of these refers to atoms with the same atomic number but different atomic masses?

If a radioactive material has a 10 year half-life, how much of a 100 g sample will be left after 30 years? A) 50 g B) 6.25 g C) 12.50 g D) 25 g

In what significant way does the modern model of the atom differ from bohr's model

Why should scientific method be used to answer a question

Energy is released during the fission of Pu-239 atoms as a result of the (1) formation of covalent bonds (2) formation of ionic bonds (3) conversion of matter to energy (4) conversion of energy to matter

A liquid that occupies a volume of 0.820 L has a mass of 2.56 kg. what is the density of this liquid in kg/L explain your answer

Using special equipment which layer of the sun atmosphere is visible during a total solar eclipse

The characteristic flame test colors of metal ions are due to atomic emission spectra. Duscuss the relationship between the absoption and emission of light and the factors responsible for flame test colors.

Should a bartender use ice and scoop directly from ice machine or use an ice holding device and scoop to make drinks and refill drinks from

What classification should this reaction have? 4Al + 3O2 → 2Al2O3

If you start with 100 grams of a radionuclide, how much will you have after two half-lives have passed?