Answer:
Thermoplastics and thermosets
Explanation:
The two key categories of plastic are thermoplastics and thermosetting plastics (thermosets). Thermoplastic products have the ability to be continually softened, melted and reshaped/recycled, for instance in injection molding or extrusion resins. However, thermoset products do not have this property.
Answer:
They have completely filled outermost shell
Explanation:
The noble gases are the rarest and occur in trace amounts in the atmosphere because they have completely filled outermost and this makes them unreactive with other elements.
Elements become abundant as they combine with other species to form compounds.
Noble gases on the other hand have a high level of stability and do not readily combine with other species.
Some of these gases are :
Helium
Neon
Argon
Krypton
Xenon
Radon
They have very high ionization energy and very low electron affinity and so will not readily react.
Mass of sodium is 23 and mass of fluirine is 19 there mass of NaF is 42
42 g = 1 mole therefor 4.5 moles will have
4.5 × 42 = 189 g
The average atomic mass: 40.078 u
electron configuration is the long list underneath the name "calcium" on the element. it starts with 1s^2s^2
I think it’s B not quite sure ! Sorry
