Helium is an inert gas, which means that it doesn't readily combine with other elements. What five other elements would you also expect to be inert gases?

Which has more volume: a kilogram of gold or a kilogram of aluminum?

In the Aloha state, you are very unlikely to be murdered! However, it is considerably more likely that your house might be burgled, your car might be stolen, or you might be punched in the nose. That said, Hawaii is still a great place to vacation or, if you are very lucky, to live. The following numbers represent the crime rates per 100,000 population in Hawaii: murder, 2.6; rape, 33.4; robbery, 93.3; house burglary, 911.6; motor vehicle theft, 550.7; assault, 125.3 (Source: Crime in the United States, U.S. Department of Justice, Federal Bureau of Investigation). Display this information in a Pareto chart, showing the crime rate for each category.

Which element has the lightest atoms?

What results when water is chemically decomposed?

You could swallow a capsule of germanium without ill effects. But, if a proton were added to each of the germanium nuclei, you would not want to swallow the capsule. Why?

If you eat metallic sodium or inhale chlorine gas, you stand a strong chance of dying. When these two elements combine, however, you can safely sprinkle the resulting compound on your popcorn for better taste. What is going on?

Consider a ball thrown straight up in the air. At what position is its kinetic energy at a maximum? Where is its gravitational potential energy at a maximum?

An ozone molecule and an oxygen molecule are both pure oxygen. How are they different?

Approximately how many atoms are present in a gram of water?

When a container of gas is heated, would you expect its molecules to speed up, slow down, or be unaffected?

Fish don't live very long in water that has been boiled and brought back to room temperature. Provide an explanation for this fact.

To become a negative ion, does an atom lose or gain an electron?

Solve the following exercise which is about operations on complex numbers.

Locate these points on the complex plane. Simplify them if necessary:

(a) $2+i$

(b) $(2+i)^2$

(c) $\frac{1}{2+i}$

(d) $|2+i|$