Listed below are sets of elements. Which period contains elements that have the following characteristics:

1) At least one is a metalloid.
2) At least one forms an ion with a charge of -2.
3) At least one is a gas.
4) At least one is a halogen

Answers-
-Oxygen, fluorine, and aluminum
-Silicon, magnesium, neon, iodine
-Arsenic, oxygen, neon, hydrogen
-Chlorine, sulfur, and silicon

If 10.g of agno3 is available, what volume of 0.25 m agno3 can be prepared

Nanotechnology, the field of trying to build ultrasmall structures one atom at a time, has progressed in recent years. one potential application of nanotechnology is the construction of artificial cells. the simplest cells would probably mimic red blood cells, the body's oxygen transporters. for example, nanocontainers, perhaps constructed of carbon, could be pumped full of oxygen and injected into a person's bloodstream. if the person needed additional oxygen-due to a heart attack perhaps, or for the purpose of space travel-these containers could slowly release oxygen into the blood, allowing tissues that would otherwise die to remain alive. suppose that the nanocontainers were cubic and had an edge length of 24 nanometers. part a part complete what is the volume of one nanocontainer? (ignore the thickness of the nanocontainer's wall.) express your answer using two significant figures. v v = 1.4ă—10â’20 l previous answers correct significant figures feedback: your answer 1.3824â‹…10â’20 = 1.382ă—10â’20 l was either rounded differently or used a different number of significant figures than required for this part. if you need this result for any later calculation in this item, keep all the digits and round as the final step before submitting your answer. part b suppose that each nanocontainer could contain pure oxygen pressurized to a density of 81 g/l . how many grams of oxygen could be contained by each nanocontainer?

What is the number of moles of chemical units represented by 9.03x10^24? and how do i show work? (dumb it down )