Answer: B) metals, non-metals, metalloids
An example of a metal is iron. A non-metal example is oxygen, which is a gas at STP (standard temperature and pressure).
A metalloid is a bit of a mix between a metal and non-metal element. It's sorta like an element that has both properties of metals and non-metals, or it's in a murky gray area. An example of a metalloid would be silicon.
Density = mass / volume
= 69g / 23 ml
= 3 g / ml.
Thus, the density of the sample is 3 grams per ml or 3g/ ml
No, since they are the strongest type of ray only elements that are dense can block them.