Two compounds of Iron are given below

FeSO4 , Fe2(SO4)3 (the oxidation state of sulphate radical is -2)

(a)Which of these compounds show +2 oxidation state for Iron?

(b) Which compound has Fe3+ ion?

(c)Write the subshell electronic configuration of Fe3+ ion.

(d) Why do the transition elements show variable oxidation states?

3. Identify the incorrect electronic configuration and correct them

(i) 1s2,2s2,2p3

(ii)1s2,2s2,2p6,3s1

(iii)1s2,2s2,2p6,2d7

(iv)1s2,2s2,2p6,3s2,3p6,3d4

answer: enthalpy

explanation:

for a exothermic reaction, the energy is released i.e. the energy of the products is lower than the energy of the reactants.

= enthaply

= energy of products

= energy of reactants

as , thus comes out to be negative. negative value of enthalpy shows that the reaction is exothermic.

acid rain does not usually kill trees directly. instead, it is more likely to weaken the trees by damaging their leaves, limiting the nutrients available to them, or poisoning them with toxic substances slowly released from the soil. the main atmospheric pollutants that affect trees are nitrates and sulphates.

considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.