Answer:
Ca
2+
<K + <Ar<Cl − <S 2−
Explanation:
Ar,K +
,Cl −
,S 2−
,Ca 2+
have the same number of electrons. Their radii would be different because of their different nuclear charges. The cation with the greater positive charge will have a smaller radius because of the greater attraction of the electrons to the nucleus. Anion with the greater negative charge will have the larger radius. In this case, the net repulsion of the electrons will outweigh the nuclear charge and the ion will expand in size. Hence the correct order will be Ca
2+ <K + <Ar<Cl − <S 2−
Answer:
Oil is a fossil fuel and timber or wood and wind is not. Hope this helps!
Answer:
613 mg
Explanation:

Number of fargday's 
Here, I = 9.20 A
t = 10.5 min
= 10.5 x 60 seconds
So, 

= 0.0208 F
Here, 2e, 2F
2F = 1 mol of Ni

1 mol = 59 gm of Ni
0.0104 mol = 59 x0.0104 gm Ni
= 0.613 gm Ni
= (0.613 x 1000 ) mg of Ni
= 613 mg of Ni
In this question given concerning the atom's electron, the number of energy sublevels present in the principal energy level n = 4 is to be determined. For this matter, it should be remembered that the number of sublevels of a certain principal energy level is equal to n. For this item, the number of sublevels is also 4. That is s, p, d and f.