Answer:
A. Warning
Explanation:
Out of all said choices, the best choice would be warning since it would fit the sentence the most.
"A Warning notifies you that danger is present." compared to:
"A Hazard notifies you that danger is present."
"A Safety notifies you that danger is present."
"A Danger notifies you that danger is present."
Answer:
The density is 5 g/cm3
Explanation:
The density (δ) is the ratio between the mass and the volume of a compound:
δ=m/v= 10 g/2 cm3= 5 g/cm3
Lanthanide belongs to period 6, and actinides belongs to period 7
Given the mass of 
=25.6 g
The molar mass of =390.35g/mol
Converting mass of to moles:
Converting mol to mol S:
Converting mol S to atoms of S using Avogadro's number:
1 mol = 
