what is the trend for the size as you go from Be to Mg to Ca? does the atomic size increase, decrease, or remain the same? how would you explain this trend in size?

the size of Ca is the greatest ,then Mg is the greater on size than Be

Explanation:

if you make the  electron configuration for each of the elements, what  is the main  difference  u gonna see ?

Be 4   1s2/2s2

Mg 12 1s2 /2s2 2p6/3s2

Ca 20 1s2 /2s2 2p6/3s2 3p6 3d/4s2

see that all the elements are in the same group but are in different period

u gonna see the last electron valance shell in Ca are too far  from its nucleus but in  Be the last electrons are too close and more attracted to the atom's nucleus , so the size of Ca is the biggest then Mg then Be

answer:

the reaction is type of combination reaction.

explanation:

on the product side, there are 2 molecules of bonded to fe   which means one atom of fe are combined two molecules of . so, balanced chemical equation becomes :

this reaction follows the reaction type of combination reaction. a combination reaction is defined as chemical reaction in which reactants combines together to form a single product.