Oxygen gas is colorless
A poor conductor of heat and electricity
It is denser than any air
Flammability: Does not burn
Occurs in many compounds : Carbon dioxide, water and iron ore
Explanation:
The reaction forms calcium hydroxide, Ca(OH)2 and hydrogen gas (H2). The calcium metal sinks in water and after an hour or so bubbles of hydrogen are evident, stuck to the surface of the metal.
Answer : The moles of given compound is, 0.064 mole
Explanation : Given,
Mass of given compound = 40 g
Atomic mass of X = 50 amu
Atomic mass of Y = 45 amu
Atomic mass of Z = 10 amu
First we have to calculate the molar mass of given compound.
The given compound formula is, 
Molar mass of
= (5 × Atomic mass of X) + (7 × Atomic mass of Y) + (6 × Atomic mass of Z)
Molar mass of
= (5 × 50) + (7 × 45) + (6 × 10) = 625 g/mol
Now we have to calculate the moles of given compound.



Thus, the moles of given compound is, 0.064 mole
Question
<em>Given the noble gas configuration of an element: [Ar] 4s2, 3d5, what is the element?
</em>
Answer:
<em>B.) Argon</em>
Hope this helps!