Start by assigning the most complicated species a coefficient of one. That species should contain the greatest number of elements, e.g. 
.
<em>(not balanced)</em>
Assign coefficients to the rest of the species based on the conservation of atoms. For instance, the left hand side of the equation now contains one atom of hydrogen H and one atoms of chlorine Cl. The left hand side shall have an identical configuration. Both zinc chloride 
and hydrogen 
should therefore have a coefficient of 1/2. (Don't panic about the fractions. They are to be eliminated in a few more steps.)
<em>(not balanced)</em>
The coefficient 1/2 in front of zinc chloride indicates the presence of 1/2 zinc atom in the right hand side of the equation. Zinc on the left hand side of the equation should accordingly have a coefficient of 1/2.
Increasing coefficients on both sides of the equation by a factor of two to eliminate all fractions. Hence the balanced equation.
(balanced)
The same set of operations should work for the second equation.
(balanced)
Note that the third equation does not accurately represent the catalytic decomposition of hydrogen peroxide 
. The balanced equation should be:
(balanced)
I think the answer is 1s²2s²2p⁶. Since neon has an atomic number of 10, we know that it needs to have 10 electrons and since it is in the second row it cannot have any d electrons which makes the first option incorrect. The second option is incorrect because the 2s⁴ can't exist since s orbitals can only hold 2 electrons. The fourth option cannot be right because it again neon cannot have d electrons due to it being in the second row.
I hope this helps. Let me know if anything is unclear.
Answer:
please mark brainlest and it's Procedure 1: One of the products was a gas that escaped into the air.
Procedure 2: A gas from the air reacted with one of the other reactants
Explanation:
the gas ca evaporate so it would'nt be a or c and b dosent make sense.
