The radius of a strontium atom is 215 pm. How many strontium atoms would have to be laid side by side to span a distance of 2.34 mm? atoms Submit Answer Retry Entire Group 9 more group attempts remaining

An element consists of 1.40% of an isotope with mass 203.973 u, 24.10% of an isotope with mass 205.9745 u, 22.10% of an isotope with mass 206.9759 u, and 52.40% of an isotope with mass 207.Y766 u. Calculate the average atomic mass, and identify the element.

One of the early models of the atom proposed that atoms were wispy balls of positive charge with the electrons evenly distributed throughout. What would you expect to observe if you conducted Rutherfords experiment and the atom had this structure?

2.81 How do binary compounds with hydrogen illustrate the concept of periodicity?

An atom has a very small nucleus surrounded by an electron cloud. Figure 2.1 represents the nucleus with a diameter of about 2 mm and describes the electron cloud as extending over 200 m. If the diameter of an atom is 1 10-8 cm, what is the approximate diameter of its nucleus?

2.26 In what region of the periodic table are you likely to find elements that form more than one stable ion?

List some characteristic properties that distinguish die metallic elements from the nonmetallic elements.

One of the best indications of a useful theory is that it raises more questions for further experimentation than it originally answered. How does this apply to Dalton’s atomic theory? Give examples.

Predict and test the behavior of a particles fired at a Rutherford atom model. Predict the paths taken by a particles that are fired at atoms with a Rutherford atom model structure. Explain why you expect the particles to take these paths. If a particles of higher energy than those in (a) are fired at Rutherford atoms, predict how their paths will differ from the lower-energy a particle paths. Explain your reasoning. Predict how the paths taken by the particles will differ if they are fired at Rutherford atoms of elements other than gold. What factor do you expect to cause this difference in paths, and why? Now test your predictions from (a), (b), and (c). Open the Rutherford Scattering simulation (http://openstaxcollege.org/I/16PhetScatter) and select the Rutherford Atom tab. Due to the scale of the simulation, it is best to start with a small nucleus, so select 20 for both protons and neutrons, mm for energy, show traces, and then start firing a particles. Does this match your prediction from (a)? If not, explain why the actual path would be that shown in the simulation. Pause or reset, set energy to max, and start firing a particles. Does this match your prediction from (b)? If not, explain the effect of increased energy on the actual path as shown in the simulation. Pause or reset, select 40 for both protons and neutrons, mm for energy, show traces, and fire away. Does this match your prediction from (c)? If not, explain why the actual path would be that shown in the simulation. Repeat this with larger numbers of protons and neutrons. What generalization can you make regarding the type of atom and effect on the path of a particles? Be clear and specific.

Do the proton and the neutron have exactly the same mass? How do the masses of the proton and the neutron compare to the mass of the electron? Which particles make the greatest contribution W the mass of an atom? Which particles make the greatest contribution to the chemical properties of an atom?