Answer: A
Explanation:
One element replaces another in a compound.
The chemical symbol for gold is AU
Answer:
Formula of oxide is 
Explanation:
The given compound consists of Fe and O.
So, mass of oxygen in sample = (mass of sample) - (mass of Fe in sample)
= (6.285 g ) - (4.396 g)
= 1.889 g
Molar mass of O = 16 g/mol and molar mass of Fe = 55.845 g/mol
So, ratio of number of moles of Fe and O (Fe : O)
= 
= 0.0787 : 0.118
= 
= 1 : 1.5
= 2 : 3
So, formula of oxide is 
non-Metals:
Nitrogen.
Oxygen.
Helium.
Sulfur.
Chlorine.
Explanation/Answer:
Metal atoms have only a few electrons in their outer shell whereas non-metal atoms have lots of electrons in their outer shell. This means that metals tend to react with non-metals. When a metal reacts with a non-metal, electrons transfer from the metal to the non-metal.
HOPE I HELPED!!