30% should be the percentage of oxygen if the total mass of fe2o3 is 160.
C) Tc-99 is a radioactive isotope also known as radioisoptope.
Answer:
+4
Explanation:
In PbO2, oxygen exhibits an oxidation number of -2 (since it's not a peroxide or superoxide):
Let the oxidation number of Pb be x. Then, for the compound to be neutral, the oxidation numbers of all atoms should add up to zero.
⇒ x + (−2) + (−2) = 0
x = +4
So the oxidation no. of Pb is +4.
I hope this helps.
Answer: The complete reaction is as follows.

Explanation:
When nucleus of two or more atoms are bombarded together then it leads to the formation of new particles with new identity. This type of reaction are called nuclear reaction.
For example, 
Here, nitrogen atom when bombarded with a neutron then it is forming hydrogen and a carbon atom.
As total atomic mass on reactant side is (14 + 1) = 15
So, the atomic mass of carbon formed on product side is (15 - 1) = 14.
The number of protons holded by this carbon atom is (7 - 1) = 6.
Therefore, we can conclude that the complete reaction is as follows.

<span>because p6 will be the group 8. You have to count the 2 electrons from the "s" block that are Group I and Group II
Group I s1
Group II s2
Group III s2 p1
Group IV s2 p2
Group V s2 p3
Group VI s2 p4
Group VII s2 p5
Group VIII s2 p6</span>