Answer:
17
Explanation:
the mass number of the element which is protons and neutrons is 17+18=35
electronic configuration is 2, 8, 7
valency of the element is 1 therefore the atomic number is 17
Answer:
Element X has valency 2 while Y Valency 2, element Y has high tendency of gaining electrons for its stability thus the compound formed will be B
elements X is positively charged while Y will be negatively charged
Answer:
Sc (Scandium) has the given electronic configuration.
Explanation:
The given electronic configuration is [Ar]
.
The last electron enters the d-subshell and hence is a d-block element known as Scandium with chemical symbol Sc.
For 4s subshell
n=4,l=0 and m ranges from -l to +l so m=0.
For 3d subshell
n=3,l=2 and m ranges from -l to +l so m can take values -2,-1,0,+1,+2
Note:
l values for subshells:
s : 0
p : 1
d : 2
f : 3 and so on.
Answer:
Rate of the reaction is 0.2593 M/s
-0.5186 M/s is the rate of the loss of ozone.
Explanation:
The rate of the reaction is defined as change in any one of the concentration of reactant or product per unit time.

Rate of formation of oxygen : 
Rate of the reaction(R) =![\frac{-1}{2}\frac{d[O_3]}{dt}=\frac{1}{3}\frac{d[O_2]}{dt}](https://tex.z-dn.net/?f=%5Cfrac%7B-1%7D%7B2%7D%5Cfrac%7Bd%5BO_3%5D%7D%7Bdt%7D%3D%5Cfrac%7B1%7D%7B3%7D%5Cfrac%7Bd%5BO_2%5D%7D%7Bdt%7D)
![R=\frac{1}{3}\frac{d[O_2]}{dt}](https://tex.z-dn.net/?f=R%3D%5Cfrac%7B1%7D%7B3%7D%5Cfrac%7Bd%5BO_2%5D%7D%7Bdt%7D)
Rate of formation of oxygen=3 × (R)

Rate of the reaction(R): 
Rate of the reaction is 0.2593 M/s
Rate of disappearance of the ozone:
![R=-\frac{1}{2}\frac{d[O_3]}{dt}](https://tex.z-dn.net/?f=R%3D-%5Cfrac%7B1%7D%7B2%7D%5Cfrac%7Bd%5BO_3%5D%7D%7Bdt%7D)
![\frac{d[O_3]}{dt}=-2\times R=-2\times 0.2593\times M/s=-0.5186M/s](https://tex.z-dn.net/?f=%5Cfrac%7Bd%5BO_3%5D%7D%7Bdt%7D%3D-2%5Ctimes%20R%3D-2%5Ctimes%200.2593%5Ctimes%20M%2Fs%3D-0.5186M%2Fs)
-0.5186 M/s is the rate of the loss of ozone.
Answer:
\large \boxed{\text{12.3 mol HCl}}
Explanation:
We need a balanced chemical equation with moles.
2HCl +Ca(OH)₂ ⟶ CaCl₂ + 2H₂O
n/mol: 12.3
The molar ratio is 2 mol H₂O:2 mol HCl.
