A sample of an alpha emitter having an activity of 0.18i is stored in a 25.0-mL sealed container at for 245 days.(a) How many alpha particles are formed during this time? (b) Assuming that each alpha particle is converted to a helium atom, what is the partial pressure of helium gas in the container after this 245-day period?
Chemistry 1 week Notes Lewis Structures 1.Calculate the total number of valence electrons in the molecule: 2.Identify the central atom of the molecule and make and arrange the rest of the atoms around it. 3. Octet Rule. The octet rule states that atoms prefer to have 8 electrons in their valence shell. C, O, N and F always follow the octet rule. An expanded octet is also possible, in that case the atom will be surrounded by 8 electrons or more. 4. Taking into account the octet rule, arrange the electrons into bonds and lone pairs. 5. Calculate the formal charge of every atom in the molecule. Formal Charge= Valence Electrons-(#electrons in lone pairs + 1/2*#atoms in bonded pairs) Unless the molecule is an ion, the overall formal charge of the molecule will be 0. You should attempt to h