Write the complete electron configuration for the iron(III) ion. Using NOBLE GAS notation write the electron configuration for the cobalt(III) ion.

The element europium exists in nature as two isotopes: 151Eu has a mass of 150.9196 u and 153Eu has a mass of 152.9209 u. The average atomic mass of europium is 151.96 u. Calculate the relative abundance of the two europium isotopes.

Neon has three stable isotopes, one with a small abundance. What are the abundances of the other two isotopes? 20Ne, mass = 19.992435 u; percent abundance = ? 21Ne mass = 20.993843 u; percent abundance = 027% 22Ne mass = 21.991383 u: percent abundance = ?

The mass spectrum of bromine (Br2) consists of three peaks with the following characteristics: Mass (u) Relative Size 157.84 0.2534 159.84 0.5000 161.84 0.2466 How do you interpret these data?

Copper atoms. (a) What is the average mass of one copper atom? (b) Students in a college computer science class once sued the college because they were asked to calculate the cost of one atom and could not do it. But you are in a chemistry course, and you can do this. (See E. Felsenthal, Wall Street Journal, May 9, 1995.) If the cost of 2.0-mm diameter copper wire (99.9995% pure] is currently 41.70 for 7.0 g, what is the cost of one copper atom?

The element silver (Ag) has two naturally occurring isotopes: 109 Ag and 107Ag with a mass of 106.905 u. Silver consists of 51.82% 107Ag and has an average atomic mass of 107.868 u. Calculate the mass of 109Ag.

3.80 Which one of the following metal samples cannot possibly exist? not? (a) a piece of gold foil 10-6 m thick (b) 5 mg of platinum (c) 10-24 mol of aluminum (d) a copper wire 0.1 mm in diameter

There are 1.699 1022 atoms in 1.000 g of chlorine. Assume that chlorine atoms are spheres of radius 0.99 and that they are lined up side by side in a 0.5-g sample. How many miles in length is the line of chlorine atoms in the sample?

Early tables of atomic weights (masses) were generated by measuring the mass of a substance that reacts with 1.00 g of oxygen. Given the following data and taking the atomic mass of hydrogen as 1.00, generate a table of relative atomic masses for oxygen, sodium, and magnesium. Element Mass That Combines with 1.00g Oxygen Assumed Formula Hydrogen 0.126 g HO Sodium 2.875 g NaO Magnesium 1.500 g MgO How do your values compare with those in the periodic table? How do you account for any differences?

The following chart shows a general decline in abundance with increasing mass among the first 30 elements. The decline continues beyond zinc. Notice that the scale on the vertical axis is logarithmic, that is, it progresses in powers of 10. The abundance of nitrogen, for example, is 1/10,000 (1/104) of the abundance of hydrogen. All abundances are plotted as the number of atoms per 102 atoms of H. (The fact that the abundances of Li, Be, and B, as well as those of the elements near Fe, do not follow the general decline is a consequence of the way that elements are synthesized in stars.) (a) What is the most abundant main group metal? (b) What is the most abundant nonmetal? (c) What is the most abundant metalloid? (d) Which of the transition elements is most abundant? (e) Which halogens are included on this plot, and which is the most abundant?