1. which type of elements will form cations, metals or non-metals? explain why.

2. list the elements that are an exception to the rule and explain why.

Explanation:

1) Cations are also called Cathode ions. They are positively charged ions. They are formed when an atom loses electron.

The tendency of an atom to lose electron decreases across the period of the periodic table. This explains why Lithium(metal) in group 1 prefers to lose an electon and attain stability where as Fluorine(non metal) accepts electron though they but belong to the same period 1 on the periodic table.

Metals form cations and not non-metals

2) The exceptions include:

Hydrogen: though it belong to group 1, yet hydrogen is not a metal but a gas at room temperature. Hydrogen has half filled orbital. Hydrogen bonds covalently.

first, consult an activity series chart to determine if al is more reactive than fe. it is, so it will replace the fe. now, one can continue with the problem.

next, make sure you have a correctly balanced equation.

3feo + 2al ==> 3fe + al2o3

now, determine which reactant (feo or al) is in limiting supply.

moles feo present = 125 g x 1 mole/71.8 g = 1.74 moles

moles al present = 25.0 g x 1 mole/26.98 g = 0.927 moles

since from the balanced equation, it take 3 mol feo for every 2 mol al, al will be limiting.

you can determine this simply by dividing moles of each by their coefficient in the balanced equation. for example: 1.74/3 = 0.58 and 0.927/2 = 0.464. al is less, so it is limiting.

finally, using the stoichiometry in the balanced eq. determine mass of fe that can be produced from 0.927 moles of al.

0.927 moles al x 3 moles fe/2 moles al x 55.8 g/mole = 77.6 g

"among the transition metal elements, manganese and zinc have a slight lowering of electronegativities. the reason behind this is that the nuclear charges of these elements are slightly weaker than the other transition metal elements due to the way their valence electrons are filled up. both manganese and zinc have their valence electrons filled up to the 4th shell with 1 pair of electrons (4s2) completely occupying it. although the electrons in the 3rd shell (3d) are yet to be paired since the outer most shell is filled up, the ability of the nucleus to attract electrons is lessened. hence,   the electronegativity (or the ability to attract electrons) is lessened."