Answer:
Mendeleev had left the noble gases out of his periodic table.
Explanation:
Mendeleev's periodic table is pictured in the image attached to the question.
Mendeleev's table obviously lacked the noble gases. The reason for this grave omission is simple; the noble gases were not known as at the time when he formulated his periodic table. There weren't any known elements whose properties were similar to the properties of the noble gases. This would have lead him to suspect their existence.
The d subshell has 5 orbitals (with each being able to hold two electrons. As such, the d orbital can hold a maximum of 10 electrons.
<span>The "d" subshell can hold a maximum of _TEN_ electrons.</span>
Answer:
63.6%
Explanation:
The given compound is:
N₂O;
The problem here is to find the percent composition of nitrogen in the compound.
First find the molar mass of the compound:
Molar mass of N₂O = 2(14) + 16 = 44g/mol
So;
Percentage composition of Nitrogen = 
x 100 = 63.6%
Answer:
0.92 kg
Explanation:
The volume occupied by the air is:
The moles of air are:
The heat required to heat the air by 10.0 °C (or 10.0 K) is:
Methane's heat of combustion is 55.5 MJ/kg. The mass of methane required to heat the air is:
H2O+Fe⇒Fe2O3+H2
When it is balanced it would be:
3H2O+2Fe⇒Fe2O3+3H2
When balancing equations, you have to make sure that all elements are equal on each side.
